Substituted nitro and cyanoguanidines and their use of increasing crop yields

ABSTRACT

Novel substituted phenyl and benzyl nitroguanidine and phenyl and benzyl cyanoguanidine compounds. Methods for increasing crop yield, inhibiting lodging of graminaceous crops, and inducing cytokinin-like responses in crop plants with said novel guanidine compounds and derivatives thereof, as well as methods for inhibiting deterioration and/or extending the shelf life of harvested fruit, vegetables, and ornamentals are disclosed.

This is a continuation-in-part of application Ser. No. 451,698 filedDec. 20, 1982, now abandoned.

The present invention relates to certain novel nitro and cyanoguanidinecompounds. Additionally, the invention relates to the use of certainguanidines useful in a variety of plant-growth regulating activities.

The guanidine compounds of the present invention include novelsubstituted phenyl and benzyl nitroguanidines and novel phenyl andbenzyl cyanoguanidines. Although nitro and cyanoguanidines are disclosedin the art, the presently-described compounds are novel.

In addition to the novel compounds of the present invention, it has beenunexpectedly discovered that certain guanidines possess heretoforeundisclosed plant growth regulating activities. These plant growthregulating actions include increases of certain crop yields, as well asinhibition in deterioration of harvested crops and ornamentals.

It is an object of the present invention, therefore, to provide thenovel nitro and cyanoguanidines described more fully below.

It is a further object of this invention to disclose methods of usingcertain guanidines as plant growth regulants. Furthermore, theseguanidines exhibit growth regulating activities in such fashion asincreasing crop yields and inhibiting deterioration of harvested cropsand ornamentals.

These and other objects of the present invention will become clearer bythe more detailed description of the invention which follows.

The invention described herein relates to novel nitro and cyanoguanidinecompounds represented by the following structural formulae (I-IV):##STR1## wherein X₁ is COCH₃, halogen, CN, CH₂ CN, C(OH)₂ CF₃, OCHF₂,OCF₃ CH₃, SCH₃, CF₃, NO₂, OCF₂ CHF₂, OCH₃, N(CH₃)₂, COOCH₃ or CH₂ OR₃,where R₃ is H or CH₃ ; Y₁ is H, halogen, or CH₃ ; Z₁ is H, CH₃, halogen,OCH₃ or CF₃ ; R₁ is H or CH₃ ; with the provisos that when X₁ is CH₃,OCH₃, F, Cl or Br and R is H, then Y₁ and Z₁ cannot both be hydrogen;and when X₁ is Cl and Z₁ and R are each hydrogen, then Y₁ cannot bemethyl; and the salts or tautomers thereof; ##STR2## wherein X₂ is H,OH, straight or branched C₁ -C₄ alkoxy, SCH₃, halogen, OCF₃, CF₃,straight or branched C₁ -C₄ alkyl or ##STR3## tetrahydro-2H-pyran-2-yl;Y₂ is H or F; Z₂ is F, H, CH₃ or OCH₃ ; W₂ is H or F; m is an integer of0, 1 or 2; R₂ is H, CH₃, C₂ H₅ or CF₃ ; with the provisos that when m is0 and R₂ is H or CH₃, then W₂, X₂, Y₂ and Z₂ cannot all be hydrogen; andwhen m is 1, then R₂, W₂, X₂, Y₂ and Z₂ cannot all be hydrogen; and thesalts or tautomers thereof; ##STR4## wherein X₃ is OCH₃, CH₃, halogen orCF₃ ; Y₃ is H, OH or halogen and Z₃ is H or Cl; with the provisos thatY₃ and Z₃ can both be hydrogen only when X₃ is OCH₃ ; and when X₃ and Y₃are each Cl, Br or I, then Z₃ cannot be hydrogen; and when X₃ is CH₃ andZ₃ is H, then Y₃ cannot be Cl; and the salts or tautomers thereof; and##STR5## wherein W₄ is H or F; X₄ is straight or branched C₁ -C₄ alkoxy,straight or branched C₁ -C₄ alkyl or F; with the provisos that when W₄is F, X₄ is H; and the salts or tautomers thereof.

Among the salt preparations of the present substituted guanidines areincluded the inorganic alkali metal, alkaline earth metal, Co, Cu, Zn,and Ag salts, along with the organic amine salts represented by thestructure, N⁺ R_(a) R_(b) R_(c) R_(d), wherein R_(a), R_(b), R_(c), andR_(d) are each selected from hydrogen and alkyl C₁ -C₃₀ straight orbranched chain and optionally substituted with one or two --OH, C₃ -C₆alkenyl or C₃ -C₆ alkynyl groups. Preferred salts of these compoundsinclude the sodium, calcium, magnesium, potassium, ammonium,methylamine, trimethylamine, dodecylamine, tributylamine,diisopropylamine, triethylamine, tetrabutylamine, and tallow-aminesalts.

The substituted phenylnitroguanidines of the present invention depictedby formula (I) above can be prepared by reaction of anappropriately-substituted aniline with approximately an equimolar amountof an N-alkyl-N-nitroso-N'-nitroguanidine in the presence of an aqueousalcoholic solution. The mixture is then heated to about 40° C., treatedwith a strong base such as sodium hydroxide, and the alcohol removedfrom the mixture by evaporation. The remaining liquid is then filtered,and the filtrate acidified with a strong mineral acid (i.e.,hydrochloric acid) to yield the desired formula (I) substitutedphenylnitroguanidine. This reaction is graphically illustrated asfollows: ##STR6## wherein R' is C₁ -C₄ alkyl; R is hydrogen and X₁, Y₁,and Z₁ are as described above. (See McKay and Wright [Journal AmericanChemical Society, 71:1968 (1949)]).

Conversion of the above-identified formula (I) substitutedphenylnitroguanidine to the corresponding 2-methyl derivative can beachieved by reaction of the substituted phenylnitroguanidine in which Ris hydrogen, with methyl iodide and silver oxide or sodium hydroxide atan elevated temperature. The reaction is graphically illustrated asfollows: ##STR7## wherein X₁, Y₁, and Z₁ are as described above.

The formula (II) substituted benzylnitroguanidines may be prepared inthe same manner as described for the preparation of the formula (I)substituted phenylnitroguanidines excepting that theappropriately-substituted benzylamine is substituted for the aniline.Alternatively, the compounds of formula (II) can be prepared by reactingthe benzylamine with nitroguanidine as shown. The product is collectedby filtration and recrystallized from the appropriate solvent. ##STR8##wherein X₂, Y₂, Z₂, and W₂ are as described above. (See Davis and Abrams[Proc. Am. Acad. Arts Sci., 61:437 (1926)]).

The formula (II) benzylnitroguanidines may also be prepared by reactionof the appropriately-substituted benzylamine with an essentiallyequivalent amount of a 2-alkyl-1(or 3)-nitro-2-thiopseudourea to producethe formula (II) substituted benzylnitroguanidines. Use of a solventsuch as ethanol in this reaction is optional. (See Fishbein and Gallahan[Journal American Chemical Society, 76:1877 (1954)] which is illustratedas follows:) ##STR9## wherein X₂, Y₂, Z₂, and W₂ are as described above.

Preparation of the substituted phenyl and benzyl cyanoguanidines (IIIand IV) is readily accomplished by dissolving or dispersing theappropriately-substituted aniline or benzylamine in hydrochloric acidand admixing the thus-formed solution or dispersion with an equimolaramount of sodium dicyanamide. In practice, it is generally desirable todisperse the sodium dicyanamide in water prior to admixture with theaniline solution or to disperse the sodium dicyanamide in ethoxyethanolfor reaction with the benzylamine. This reaction is illustrated asfollows: ##STR10## wherein R₄, X₅, Y₅, Z₅, W₅, m, and n are aspreviously described.

The present invention also relates to methods for regulating plantgrowth and in particular, for increasing crop yield of underground stemcrops, underground stem ornamentals, root crops, graminaceous crops,forage crops, tomatoes, tobacco, sunflowers, cotton, cucurbits, andfruit. This method involves application to the foliage of subject plantsor to soil containing the seeds or other propagating organs thereof of acropyield-enhancing amount of a compound having the following structuralformula (V): ##STR11## wherein W₅ is H, F or Cl; X₅ is H, straight orbranched C₁ -C₄ alkyl, halogen, CN, NO₂, CH₂ CH.OCHF₂, OCF₂ CHF₂, OCF₃,CF₃, C₁ -C₄ alkoxy, ##STR12## tetrahydro-2H-pyran-2-yl, OH, C(OH)₂ CF₃,SCH₃, COCH₃, N(CH₃)₂, COOCH₃ or CH₂ OR₃, where R₃ is H or CH₃ ; Y₅ is H,OH, OCH₃, CH₃ or halogen; Z₅ is H, CH₃, halogen, OCH₃ or CF₃ ; R₄ is H,CH₃, C₂ H₅ or CF₃ ; R₅ is H or CH₃ ; R₆ is NO₂ or CN; m is an integer of0, 1 or 2; n is an integer of 0 or 1; and the salts of tautomersthereof.

Compounds depicted by formula (V) above in which X₅ is a substituentother than hydrogen; Y₅, Z₅, n, R₅, and R₆ are as described above; m is0 or 1; R₄ is H; and W₅ is H, represent preferred crop-yield-enhancingcompounds of the present invention. Especially preferred compounds whichenhance crop yields are the phenyl compounds depicted by formula (V),wherein n is 0; X₅ is CH₃, halogen, CF₃, OCF₃, OCHF₂, C(OH)₂ CF₃, orCOCH₃ ; Y₅ is H, halogen, or CH₃ ; Z₅ is H, CH₃, OCH₃, or halogen; R₅ isH; R₆ is NO₂ ; and W₅ is H; provided that when X₅ is chloro and Z₅ ishydrogen, Y₅ cannot be methyl; and the pharmaceutically-acceptable saltsor tautomers thereof.

Yet another preferred group of crop-yield-enhancing compounds of theinvention includes the benzyl compounds depicted by formula (V), whereinn is 1; X₅ is H, OCH₃, CH₃ or halogen; Y₅ is H, F or OCH₃ ; Z₅ ishydrogen; R₅ is H; R₆ is NO₂ ; m is O; R₄ is H or CH₃ ; and W₅ is H.

In addition to the plant-growth-regulating and crop-yield-enhancingactions of the formula (V) compounds, these compounds surprisingly arefound to be useful for preserving the freshness and/or inhibitingdeterioration of harvested crops, particularly recently-harvested greenfruit, vegetables, and leafy ornamentals, especially recently-harvestededible leafy vegetables such as lettuce, spinach, beet greens, endive,swiss chard, escarole, and chickory.

The above-described procedures for the preparation of the formula (I)substituted phenylnitroguanidines and formula (II) substitutedbenzylnitroguanidines are likewise useful for the preparation of thevariously substituted formula (V) nitroguanidines using the appropriateaniline or amine. The reaction may be illustrated as follows: ##STR13##wherein R₆ is NO₂ ; R₅ is H; and R₄, m, n, W₅, X₅, Y₅, and Z₅ are asdescribed above.

In practice, it has been found that the formula (V) substitutedguanidines of the present invention are highly effectivecrop-yield-enhancing agents when applied in effective amounts to thefoliage of crops or to soil containing seeds or other propagatingorgans, such as corms, rhizomes, bulbs, or seed pieces thereof.Moreover, it has been found that the formula (V) compounds of thisinvention are especially effective for increasing crop yield ofunderground stem crops, underground stem ornamentals, root crops,graminaceous crops, forage crops, tomatoes, tobacco, sunflowers, cotton,cucurbits, and fruit; and, further, that crop-yield enhancement can beachieved with both solid and liquid formulations containing thebiologically-active formula (V) substituted guanidine.

Surprisingly, it has also been discovered that the application of aformula (V) substituted guanidine to the foliage of the above-said cropsor to soil containing seeds or other propagating organs thereof, in anamount sufficient to provide about 0.06 to 5.0 kg/hectare (preferablyabout 0.125 to 2.0 kg/hectare), causes the treated plants to increasethe size and/or the number of the tubers, corms, rhizomes, bulbs,kernels, gourds, bolls, or fruit produced thereby. Additionally, it isnoted that treatment of underground stem crops, underground stemornamentals, or root crops with the formula (V) guanidine compounds ofthe present invention markedly improves uniformity in size and shape ofthe tubers, corms, rhizomes or bulbs produced by the treated plants.These results are especially noticeable in potato crops (e.g., whitepotatoes) wherein treated plants are found to produce: (1) a greaternumber of potatoes, (2) a substantially increased total weight ofpotatoes, (3) more superior grade Number 1 potatoes, and (4) fewerNumber 2 potatoes.

When the formula (V) substituted guanidines are to be applied toharvested fruit, vegetables, or ornamentals to inhibit theirdeterioration and improve their freshness and shelf life, the formula(V) substituted guanidine is dissolved in water, about 0.01 to 800.0ppm, and applied as an aqueous solution in the form of a dip or a sprayto the fruit, vegetable, or ornamental which is to be protected. Forbest results, the fruit, vegetables, or ornamentals which are to beprotected against rapid deterioration may be sprayed with the aqueoussolution containing from 0.01 to 800.0 ppm of the formula (V)substituted guanidine about one to two days before harvest and theneither sprayed or dipped in the aqueous solution of the formula (V)guanidine again within about 24 hours following harvest. If multipleapplications are impractical, the harvested crop may be dipped orsprayed with an aqueous solution of active ingredient shortly afterharvest (preferably within 24 hours following harvest).

It has also been found that application of the formula (V) substitutedguanidines to the foliage of graminaceous crops such as rice, at thepanicle development stage, inhibits lodging of the rice due to adverseweather conditions.

The remarkably unique plant-growth-regulant activity of the formula (V)compounds of the present invention is further demonstrated by thephysiological alterations noted in tobacco plants that have been treatedprior to maturation, preferably between the early seedling stage andplant topping, with a formula (V) substituted guanidine compound. Whentobacco plants, approximately 5 to 125 centimeters in height, aretreated with about 0.025 to 2.50 kg/hectare (preferably 0.1 to 0.3kg/hectare) of a formula (V) substituted nitro or cyanoguanidine,senescence in the lower, more mature, tobacco leaves is delayed orretarded until senescence in essentially all of the leaves of thetreated plant begins. Thus, harvesting of the mature tobacco leaves canbe completed in a single, or in at most, two cuttings, whereas, it hadnot been uncommon in the past to require three or four cuttings.

In addition to these advantages, it is also noted that tobacco plantstreated with the formula (V) nitro or cyanoguanidine provide anincreased yield of tobacco compared to untreated plants.

Although Applicants do not want to be limited by theory, it is seenthrough experimentation that, as suggested by the preceding discussion,compounds of this invention are true plant-growth regulators, asmeasured by a number of criteria. Not only are they able to increasecrop yields, they are also able to induce regulator effects inlaboratory tests.

These effects fall into at least three classes of responses, all ofwhich are consistent with the conclusion that these compounds representa novel class of cytokinins. The observed responses include enhancedgrowth effects on translocation, as well as enhanced chlorophyllbiosynthesis in some tissues with decreased chlorophyll degradation(senescence) in others. These responses suggest that the present classof compounds would be expected to elicit other known cytokinin planttissue responses in addition to those described below and that a numberof uses of these compounds pertaining to translocation of metabolites tostorage organs or to temporary storage sites in the tissues orpertaining to delaying senescence and enhancing growth of certain planttissues are implied from the mode of action of the compounds.

The compounds of the present invention have been found to substitute fora well-investigated cytokinin, N⁶ -benzyladenine, in promoting growth ofcytokinin-dependent soybean callus in tissue culture. The cucumbercotyledon bioassay, described below, was used to define the compoundswhich possess cytokinin-like activity. As with many hormone-typebioassys, the response is log-linear with respect to concentration ofcompound required to elicit a response. The results the present compoundhad are two-fold, enhanced growth and enhanced rate of chlorophyllbiosynthesis.

Growth promotive effects also were shown in two other systems as well.The growth of cotyledons could be stimulated in young, whole, radishseedlings with little effect on the growth of the rest of the seedling,that the length of the radicle may be reduced, and a more rapidenlargement in isolated leaf disks from lima bean could be effected.

Furthermore, the present compounds also direct the translocation ofsucrose within the potato plant from one site to another. Whole potatoplants receiving early hydroponic treatment with the present compoundswere also found effective in early tuber development in that a greaterproportion and weight of larger tubers were evident about half-waythrough tuber development.

Another property of the compounds was observed in senescence retardationof various plant systems. This was manifest by chlorophyll retention intissues which were otherwise becoming yellow, indicating degrading ofchlorophyll. This occurred with application to the foliage in spots orstreaks (e.g., potato leaves), in leaf disks of cocklebur or of Romaineleaf lettuce, and in very young potato plants under adverse conditions.

The above-identified formula (V) guanidine compounds are highlyeffective for beneficially altering the growth and/or enhancing theyield of a wide variety of crops, such as:

Underground Stem Crops, including:

Solanum tuberosum L.--white potato,

Helianthus tuberosus--Jerusalem artichoke,

Coloeasia antiguorum--Taro,

Coloeasia esculenta--dasheen,

Allium cepa--onion,

Allium sativum--garlic,

Allium porrum--leek,

Allium schoenoprasum--chive, and

Allium ascalowicum--shallot;

Underground Stem Ornamentals, including:

Corms such as crocus or gladiolus,

Bulbs such as tulips and hyacinths, and

Rhizomes such as iris, canna or Solomon's seal;

Root Crops, including:

Beta vulgaris--common beat, mangels and/or chard,

Daucus carota--carrot,

Tragopogon porrifolius--salsify,

Pastinaca sativa--parsnip

Raphanus sativus--radish,

Brassica rapa--turnip

Brassica napobrassica--rutabaga,

Ipomoea batatus--sweet potato, yam,

Pioscroa alata--true yam,

Manihot esculenta--cassava, and

Beta vulgaris--sugar beet;

Graminaceous Crops, including:

Hordeum vulgare--barley

Triticum aestivum--wheat, and

Oryza sativa--rice;

Cucurbits, including:

Cucumis sativus, L.--cucumber, and

Cucurbita pepo, L.--pumpkin

Fruit, including:

Pyrus malus L.--apple;

Malvaceae, including:

Gossypium hirsutum--cotton, and

Lycopersicon esculeutum--tomatoes.

Surprisingly, it has also been found that certain of the formula (V)nitroguanidines and cyanoguanidines, for example, those in which Y₅ andW₅ are hydrogen; Z₅ and X₅ are halogen; and R₄, R₅, R₆, m, and n are asdescribed above, are effective for increasing crop yields of rice (Oryzasativa), sunflowers (Helianthus annus, L.), alfalfa (Medicago sativa,L.), forage grasses (such as Agrostis spp., Bromus spp., Dactylis spp.,and Pheleum spp.) and tobacco (Nicotiana tobacum, L.). When applied totobacco plants prior to plant topping, and preferably when the plantsare between about 5 cm and 140 cm in height, it has been found that theabove-said nitroguanidines or cyanoguanidines retard senescence of thelower, more mature, tobacco leaves until younger leaves at the top ofthe treated plant are ready for harvest. This treatment represents agreat advantage for the tobacco farmers because the number of pickingsrequired for harvesting the crop are reduced. The tobacco from thesetreated plants is also more uniform than untreated tobacco.

These formula (V) compounds have the further advantage, when applied torice or sunflowers, of increasing stem stiffness and/or stem diameter,thereby inhibiting the incidence of lodging of these crops.

Among the most effective compounds found to induce the above-mentioneddesirable improvements in crops and crop yields are:

1-Nitro-3-(α,α,α-trifluoro-m-tolyl)guanidine;

1-(3,4-Dichlorophenyl)-3-nitroguanidine;

1-(m-Chlorophenyl)-3-nitroguanidine;

1-(3,5-Dichlorophenyl)-3-nitroguanidine;

1-(4-Chloro-α,α,α-trifluoro-m-tolyl)-3-nitroguanidine;

1-Nitro-3-(3,5-xylyl)guanidine;

1-(4-Bromo-m-tolyl)-3-nitroguanidine;

1-Nitro-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine;

1-(3-Chloro-4-fluorophenyl)-3-nitroguanidine;

1-(m-Acetylphenyl)-3-nitroguanidine;

1-(m-Methoxybenzyl)-3-nitroguanidine;

1-(3,5-Dichlorophenyl)-1-methyl-3-nitroguanidine;

1-Cyano-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine;

1-(3-Chloro-4-fluorophenyl)-3-cyanoguanidine;

1-Cyano-3-(3,5-dichlorophenyl)guanidine;

1-(3-Chloro-4-hydroxyphenyl)-3-nitroguanidine;

1-(m-Methylbenzyl)-3-nitroguanidine;

1-Cyano-3-(m-methoxybenzyl)guanidine;

1-Nitro-3-veratrylguanidine;

1-(m-Fluorobenzyl)-3-nitroguanidine;

1-(p-Fluorobenzyl)-3-nitroguanidine;

1-(m-Bromophenyl)-3-nitroguanidine;

1-Nitro-3-(3,4,5-trichlorophenyl)guanidine;

1-(m-Bromophenyl)-3-cyanoguanidine;

1-Cyano-3-(α,α,α-trifluoro-m-tolyl)guanidine;

1-Benzyl-3-cyanoguanidine;

1-(m-Iodophenyl)-3-nitroguanidine;

1-Nitro-3-[m-(2,2,2-trifluoro-1,1-dihydroxyethyl)phenyl]guanidine;

1-(4-Fluoro-m-tolyl)-3-nitroguanidine;

1-Nitro-3-(3,4-xylyl)guanidine;

1-(α-Methoxy-m-tolyl)-3-nitroguanidine;

1-Benzyl-3-nitroguanidine;

1-(4-Chloro-m-tolyl)-3-nitroguanidine;

1-[m-(Difluoromethoxy)phenyl]-3-nitroguanidine;

1-Nitro-3-(m-propoxybenzyl)guanidine;

1-(α-Methylbenzyl)-3-nitroguanidine;

1-(2-Fluoro-5-methylbenzyl)-3-nitroguanidine;

1-(2-Fluoro-5-methoxybenzyl)-3-nitroguanidine; and

1-Nitro-3-[m-(trifluoromethoxy)phenyl]guanidine.

Advantageously, the compounds of the present invention can be formulatedas solid or liquid compositions which may be dispersed in a liquid orsolid diluent for application to the foliage of plants or to the soil inwhich they are grown. The substituted guanidines of the invention may beformulated as flowable concentrates, emulsifiable concentrates, wettablepowders, dust, dust concentrates, and granular formulations.

A typical flowable liquid concentrate can be prepared by millingtogether, on a weight basis, about 46% of the substituted guanidine withabout 0.4% colloidal magnesium aluminum silicate, about 1.5% naphthaleneformaldehyde condensate, about 8% polyethylene glycol, about 0.1%nonylphenol ethylene oxide condensate (9-11 moles ethylene oxide), about0.1% of a dispersing agent (i.e., sodium lignosulfonate), about 0.07%citric acid, about 46% water, and about 0.06% xanthan gum. Thisconcentrate is dispersed in water for application as a liquid spray.

Another flowable liquid concentrate is prepared by admixing or millingtogether about 40%, by weight, of the substituted nitro orcyanoguanidine, about 0.40% colloidal magnesium aluminum silicate, about1.50% sodium salts of polymerized alkyl naphthalene sulfonic acids,about 8.0% propylene glycol, about 0.1% ethoxylated octylphenol, about0.1% nonylphenoxy polyethoxy ethanol, about 0.07% citric acid, about0.06% xanthan gum, about 0.10% paraformaldehyde and about 49.77% water.

Emulsifiable concentrates can be prepared by dissolving, on a weightbasis, about 10% of the active guanidine in about 38% ofN-methylpyrrolidone, about 35% of a mixture of substituted benzenes, andabout 10% of a spreader activator, having ingredientsalkylarylpolyoxyethylene glycol, free-fatty acid and propanol, withabout 7% by weight of a nonionic surfactant, such as octylphenoxypolyethoxy ethanol, nonylphenoxy polyethoxy ethanol, or the like. Thisconcentrate is dispersed in water for application as a liquid spray. Itmay also be applied, undiluted to granular carriers, such as corncobgrits, kaolin or attapulgite, to provide a granular formulation usefulfor application to soil in which any of the above-mentioned crops aregrown.

Emulsifiable concentrates can also be prepared by dissolving, on aweight basis, about 11% of the active guanidine in about 57% ofN-methylpyrrolidone, about 24% octyl alcohol, and about 8%polyoxyethylated castor oil.

A typical wettable powder can be prepared by grinding together, on aweight basis, about 20 to 45% of a finely-divided carrier (i.e., kaolin,bentonite, diatomaceous earth, attapulgite, or the like), about 45 to80% of the active compound, about 2 to 5% of a dispersing agent (i.e.,sodium lignosulfonate), and about 2 to 5% of a nonionic surfactant(i.e., octylphenoxy polyethoxy ethanol, nonylphenoxy polyethoxy ethanol,or the like). This formulation is generally dispersed in water forapplication as a liquid spray.

Advantageously, the guanidines of this invention may also be prepared asaqueous sprays or dips containing about 0.01 to 800.0 ppm of saidguanidine. Said formulations are useful, as such, for treatment ofharvested fruit, vegetables, and leafy ornamentals to inhibit theirdeterioration.

To facilitate understanding of the invention, the followingnonlimitating examples are presented for the purpose of illustrating thepresent invention. Unless otherwise noted, all parts are by weight.

EXAMPLE 1 Preparation of 1-nitro-3-(3,4,5-trichlorophenyl)guanidine

To a slurry of N-methyl-N-nitroso-N'-nitroguanidine 3.3 g (0.0225 mol)in 200 ml of a 50% aqueous ethanol mixture is added 5.0 g (0.025 mol) of3,4,5-trichloroaniline. This mixture is heated to 40° C. for 72 hoursand then treated with one equivalent of NaOH to decompose excessN-methyl-N-nitroso-N'-nitroguanidine. The mixture is then filtered andacidified with concentrated HCl to give 1.6 g of a yellow solid which,when recrystallized, gives 1.4 g of the desired product. The meltingpoint of the product is 209.5° C. dec.

The above procedure can be repeated except that the appropriate anilineis substituted for 3,4,5-trichloroaniline, and the period of heating isadjusted to yield the substituted nitroguanidines reported in Table Ibelow. The reaction may be illustrated as follows: ##STR14##

                  TABLE 1                                                         ______________________________________                                                                         Melting Point                                X.sub.1     Y.sub.1     Z.sub.1  (°C.)                                 ______________________________________                                        F           H           H        172-174                                      Cl          H           H        162-163                                      Br          H           H        180-181                                      I           H           H        183-186                                      CF.sub.3    H           H        154.5-155.5                                  CH.sub.3    H           H        122.14 124                                   CH.sub.2 CN H           H        165-167                                      CH.sub.2 OCH.sub.3                                                                        H           H        106-107.5                                    CH.sub.2 OH H           H        138-140                                      COCH.sub.3  H           H        158-160                                      COCF.sub.3.H.sub.2 O                                                                      H           H        172-174                                      SCH.sub.3   H           H        155-157                                      OCHF.sub.2  H           H        122-124                                      OCF.sub.3   H           H        135-136.5                                    OCF.sub.2 CHF.sub.2                                                                       H           H        158-160                                      OCH.sub.3   H           H        151.5-153.5                                  OC.sub.2 H.sub.5                                                                          H           H        137.5-139                                    CN          H           H        207-208                                      NO.sub.2    H           H        194-196                                      H           H           H                                                     N(CH.sub.3).sub.2                                                                         H           H        158-159.5                                    COOCH.sub.3 H           H        173-175                                      Cl          F           H        171-173                                      Cl          Cl          H        155-156.5                                    Cl          CH.sub.3    H        176-177                                      CF.sub.3    F           H        168-170                                      CF.sub.3    Cl          H        212-213                                      CH.sub.3    F           H        182-183.5                                    CH.sub.3    Br          H        182-183                                      CH.sub.3    Cl          H        196.5-198                                    CH.sub.3    CH.sub.3    H        161-162.5                                    Cl          H           Cl       218-219                                      Br          H           Br       243 dec.                                     Br          H           CH.sub.3 201-203                                      CH.sub.3    H           CH.sub.3 188-189                                      OCH.sub.3   H           CF.sub.3 152-154                                      CF.sub.3    H           CF.sub.3 224-226                                      OCH.sub.3   H           OCH.sub.3                                                                              208-209                                      Cl          Cl          Cl       210 dec.                                     COOH        H           H        245-47                                       OC.sub.6 H.sub.5                                                                          H           H        138-39.5                                     H           Br          H        189-191                                      H           CF.sub.3    H        170-72                                       H           CH.sub.2 COOH                                                                             H        199-200.5                                    H           OCF.sub.2 CHF.sub.2                                                                       H        152-53.5                                     NO.sub.2    F           H        171-72                                       Cl          CH.sub.3 O  H        185.5-86.5                                   NH.sub.2    CH.sub.3    H        170.5-72.5                                   CH.sub.3    CH.sub.3    CH.sub.3 207-09                                       ______________________________________                                    

EXAMPLE 2 Preparation of1-(3,5-dichlorophenyl)-2-methyl-3-nitroguanidine PART A ##STR15##

Methyl iodide (10 ml) is added to the nitroguanidine (2 g, 0.008 mol)and silver oxide (0.92 g, 0.004 mol), and the suspension refluxed. Aftertwo hours, the black suspension gradually becomes a yellow suspension.It is cooled to room temperature and filtered through diatomaceousearth. After concentration in vacuo, the crude product is recrystallizedfrom Et₂ O/THF to give 1.6 g (76%) of a white solid with melting point136° C.-138° C. This procedure is also effective for preparing1-methyl-3-nitro-1-(α,α,α,4-tetrafluoro-m-tolyl)guanidine, melting point169°-171° C.

PART B Preparation of 1-(4-Bromo-m-tolyl)-1-methyl-3-nitroguanidine##STR16##

Sodium hydroxide (50% aq, 0.94 ml, 0.012 mol) is added in one portion toa homogeneous mixture of phenylnitroguanidine (3.00 g, 0.011 mol) andaqueous ethanol (5:1 ethanol:water, v/v). Methyl iodide (4.79 ml, 10.9g, 0.077 mol) is added and the resultant mixture is stirred for 22 hoursat 25° C. The white precipitate is filtered with water wash andrecrystallized from ethanol to afford pure product (2.35 g, 74.6%,melting point 162° C.-164° C.).

PART C Preparation of 1-benzyl-1-methyl-3-nitroguanidine ##STR17##

N-Methylbenzylamine (9.89 g, 0.082 mol) is added dropwise to asuspension of MNNG (10.0 g, 0.068 mol) in aqueoos ethanol (1:1ethanol:water, v/v) at 25° C. A gradual exotherm to 44° C. occurs overthe next 15 minutes. After stirring for 42 hours at ambient temperature,the white slurry is filtered. The resultant white solid (7.13 g) isrecrystallized from hexanes:ethanol to afford pure product (whitecrystals, 6.06 g, 43.0%, melting point 103° C.-107° C.).

EXAMPLE 3 Preparation of 1-(m-fluorobenzyl)-3-nitroguanidine

The compound m-fluorobenzylamine (7.5 g, 0.06 mol) is added to a slurryof N-methyl-N-nitroso-N'-nitroguanidine (8.33 g, 0.056 mol) in a 50%aqueous ethanol mixture. The thus-formed mixture is stirred for 18hours, then treated with 1N NaOH (150 ml), and the mixture filtered. Thefiltrate is acidified with concentrated HCl, and the reaction mixture isthen filtered to obtain the desired fluffy white solid product (10.6 g)having a melting point of 177° C.-179° C.

The above procedure is repeated using the appropriately substitutedamine and 2-methyl-1(or 3)-nitro-2-thiopseudourea to obtain thecompounds illustrated in Table II below. The reaction is graphicallyillustrated as follows: ##STR18## wherein m, R₂, W₂, X₂, Y₂, and Z₂ areas defined above.

                                      TABLE II                                    __________________________________________________________________________     ##STR19##                                                                    W.sub.2                                                                           X.sub.2   Y.sub.2   Z.sub.2                                                                           R.sub.2                                                                            m Melting Point (°C.)                 __________________________________________________________________________    H   H         H         H   H    0 179-180.5                                  F   H         H         H   H    0 181-183                                    H   OH        H         H   H    0 122-125                                    H   OCH.sub.3 H         H   H    0 134-136                                    H   OC.sub.2 H.sub.5                                                                        H         H   H    0 125-128                                    H   OC.sub.3 H.sub.7 - -n                                                                   H         H   H    0 140.5-141.5                                     ##STR20##                                                                              H         H   H    0 93-98                                      H                                                                                  ##STR21##                                                                              H         H   H    0 110.5-113                                  H   OCF.sub.3 H         H   H    0 138-139                                    H   SCH.sub.3 H         H   H    0 149-152                                    H   F         H         H   H    0 177-179                                    H   Cl        H         H   H    0 166-167                                    H   Br        H         H   H    0 157-159                                    H   I         H         H   H    0 167-169                                    H   CH.sub.3  H         H   H    0 151-153                                    H   C.sub.2 H.sub.5                                                                         H         H   H    0 119-120.5                                  H   CF.sub.3  H         H   H    0 164-165                                    H   H         F         H   H    0 205-206                                    H   H         Cl        H   H    0 195-197                                    H   H         Br        H   H    0 172-174                                    H   H         CH.sub.3  H   H    0 181-183                                    Cl  Cl        H         H   H    0 220-222                                    F   CH.sub.3  H         H   H    0 198-198.5                                  F   OCH.sub.3 H         H   H    0 162-165                                    Cl  H         Cl        H   H    0 220-202                                    F   H         F         H   H    0 209-211                                    F   H         H         CH.sub.3                                                                          H    0 171.5-173                                  F   H         H         F   H    0 186-188                                    F   H         H         OCH.sub.3                                                                         H    0 149-151                                    F   H         H         H   H    1 153.5-154.5                                H   OCH.sub.3 H         H   H    1 88-89                                      H   OCH.sub.3 H         H   H    2 122-123                                    H   H         H         H   CH.sub.3                                                                           0 115-116.5                                  H   H         H         H   CF.sub.3                                                                           0 149-151                                    H   H         H         H   C.sub.2 H.sub.5                                                                    0 129.5-130.5                                F   H         H         H   CH.sub.3                                                                           0 99-102                                     H   H         H         H   CH.sub.3                                                                           0 (+) isomer                                                                    126-127                                    H   H         H         H   CH.sub.3                                                                           0 (-) isomer                                                                    127.5-128                                  H   CH.sub.3  H         H   CH.sub.3                                                                           0 140-143                                    H   OCH.sub.3 H         H   CH.sub.3                                                                           0 126-130                                    H   H         F         H   CH.sub.3                                                                           0 133-136                                    Cl  H         H         H   H    0 168-170                                    OCH.sub.3                                                                         H         H         H   H    0 202-205                                    H   CN        H         H   H    0 206 dec.                                   H   OC.sub.6 H.sub.5                                                                        H         H   H    0 145-147                                    H   COOCH.sub.3                                                                             H         H   H    0 158-162                                    H   CH.sub.2 CH.sub.2 COOC.sub.2 H.sub.5                                                    H         H   H    0 77-79                                      H   OSO.sub.2 CH.sub.3                                                                      H         H   H    0 134-137                                    H   H         OCH.sub.3 H   H    0 191.5-192.5                                H   H         N(CH.sub.3).sub.2                                                                       H   H    0 211-213                                    H   H         CH.sub.2 N(CH.sub.3).sub.2                                                              H   H    0 136-144                                    H   H         CH.sub.2 NH.sub.2                                                                       H   H    0 260°                                H   H         CH.sub.2 CH.sub.2 COOC.sub.2 H.sub.5                                                    H   H    0 124-126                                    H   H         CN        H   H    0 166-168                                    OCH.sub.3                                                                         H         OCH.sub.3 H   H    0 200-201                                    H   H         H         H   C.sub.6 H.sub.5                                                                    0 236-237                                    H   F         H         H   CH.sub.3                                                                           0 135-138                                    H   OCH.sub.3 OCH.sub.3 H   H    0 152.5-153.5                                H   Cl        Cl        H   H    0 208-210                                    H   OCH.sub.2O          H   H    0 207.5-209                                  H   OCH.sub.3 H         OCH.sub.3                                                                         H    0 166-168                                    H   CH.sub.3  H         CH.sub.3                                                                          H    0 178-180                                    H   Cl        H         Cl  H    0 218-219                                    H   H         H         H   CH.sub.3                                                                           1 178-180                                    H   H         H         H   CH.sub.2 C.sub.6 H.sub.5                                                           0 199.5-201                                  OCH.sub.3                                                                         H         H         H   CH.sub.3                                                                           0 188-192                                    __________________________________________________________________________

EXAMPLE 4 Preparation of 1-cyano-3-(3,5-dichlorophenyl)guanidine

To a solution of 4.45 g (0.05 mol) of sodium dicyanamide in 50 ml of 1NHCl is added 8.1 g (0.05 mol) of 3,5-dichloroaniline in 50 ml of H₂ O.The mixture is heated to about 80° C. to 100° C. for two hours. Themixture is then cooled, and the precipitated solids are recovered byfiltration, washed and dried to give 8.75 g of the desired producthaving a melting point of 196° C.-198° C.

Following the above procedure, but substituting the appropriatelysubstituted aniline for 3,5-dichloroaniline, provides the compoundsreported in Table III below. The reaction may be graphically illustratedas follows: ##STR22## wherein X₃, Y₃, and Z₃ are as described above.

                  TABLE III                                                       ______________________________________                                         ##STR23##                                                                    X.sub.3    Y.sub.3    Z.sub.3 Melting Point (°C.)                      ______________________________________                                        H          H          H       195-196                                         CF.sub.3   H          H       203-206                                         Cl         H          H                                                       Br         H          H       236-237                                         NO.sub.2   H          H       234-236                                         OCH.sub.3  H          H       182-184                                         CH.sub.3   H          H                                                       CN         H          H       234-235.5                                       Cl         OH         H                                                       Cl         F          H       214.5-216                                       CF.sub.3   Cl         H       194-196                                         CF.sub.3   F          H       146-148                                         CH.sub.3   Br         H       223-225                                         Cl         CH.sub.3   H       232-234                                         Cl         Cl         H       226-228                                         Cl         H          Cl      196-198                                         COCH.sub.3 H          H       175-178                                         COOH       H          H                                                       N(CH.sub.3).sub.2                                                                        H          H       163.5-164.5                                     COOCH.sub.3                                                                              H          H       212-213                                         H          Cl         H                                                       H          OCH.sub.3  H                                                       H          NHCOCH.sub.3                                                                             H                                                       H          CH.sub.3   H                                                       H          N(CH.sub.3).sub.2                                                                        H                                                       H          OH         H                                                       H          COOH       H                                                       H          COCH.sub.3 H                                                       H          N(C.sub.2 H.sub.5).sub.2                                                                 H                                                       CH.sub.3   CH.sub.3   H                                                       CH.sub. 3  H          CH.sub.3                                                                              224-227                                         CF.sub.3   H          CF.sub.3                                                                              263-265                                         ______________________________________                                    

Following the procedure of Example 4, but substituting theappropriately-substituted benzylamine for 3,5-dichloroaniline, providesthe compounds reported in Table IV below. The reaction may beillustrated as follows: ##STR24## wherein W₄ and X₄ are as describedabove.

                  TABLE IV                                                        ______________________________________                                         ##STR25##                                                                    W.sub.4                                                                             m      X.sub.4 Y.sub.4                                                                            Z.sub.4                                                                             R.sub.2                                                                            Melting Point (°C.)               ______________________________________                                        H     0      H       H    H     H    100-101                                  F     0      H       H    H     H    129-130                                  H     0      OCH.sub.3                                                                             H    H     H    112-114                                  H     0      CH.sub.3                                                                              H    H     H      97-98.5                                H     0      F       H    H     H    134-136                                  H     0      H       Cl   H     H    153-155                                  H     0      H       F    H     H    134-135                                  F     0      H       H    CH.sub.3                                                                            H    123-124                                  F     0      H       H    OCH.sub.3                                                                           H    129-131                                  H     0      H       Cl   H     CH.sub.3                                                                           171-174                                  H     0      H       H    H     CH.sub.3                                                                           156-158                                  ______________________________________                                    

EXAMPLE 5 Cucumber cotyledon greening bioassay for cytokinins

To evaluate test compounds for cytokinin stimulation in cucumber plants,plant cucumber seeds (National Pickling variety), placed in coveredplastic trays, were soaked in moist vermiculite and were exposed to agreen safelight. The trays were then placed in a dark environment forsix days at 30° C.

Test solutions of compounds were prepared according to a 1 to 8 dilutionseries including 0.0156 ppm, 0.125 ppm, 1.0 ppm, 8 ppm, and 64 ppm oftest compound. The solutions all contained 40 mM KCl, glass-distilled H₂O, and up to 1.25% acetone. (The compounds were initially dissolved in100% acetone). Ten ml of diluted compounds were placed in a 10 cm petridish containing three layers of Whatman #1 cellulose filter papers.Again using dim green light, the cotyledons from the seedlings wereexcised using great care to discard the hook region, and eight pairs (16cotyledons) were placed in each dish with the inner (upper) cotyledonsurfaces downward. These were then incubated in the dark at 30° C.overnight (17 to 21 hours). These were placed in the dishes underfluorescent light, with an intensity of 12-14 W per square meter, for aperiod of three hours. The dishes were kept at 20° C. or less in thedark while the cotyledons were sequentially collected and put into lotsin large test tubes containing 5 ml of dimethylformamide. The tubes weresealed with Parafilm and placed at 4° C. in the dark, overnight, or at30° C. in the dark for four hours to extract the chlorophyll.

The leachate was analyzed for absorbance at 663 nanometers (nm).

The cotyledons were removed and their surface areas were measured with aleaf-area meter. Data obtained with N⁶ -benzyladenine, a knowncytokinin, were used to establish conditions for the test and to depictthe cytokinin-like responses of the test compounds. Graphic curves weredrawn to show (1) the increase in rate of chlorophyll biosynthesis(absorbance of leachate at 663 nm), and (2) the increase in cotyledonsurface area (expansion). These data are presented below in FIGS. I andII. A compound of the present invention,1-nitro-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine, is also evaluated inthis test. A curve of the two responses obtained is compared with N⁶-benzyladenine (a "Standard Cytokinin" against which other compounds canbe compared). FIG. I reports greening data obtained in this test withthe above-said compounds. FIG. II shows the expansion of the surfacearea of the cotyledon obtained with said compounds.*

The dose-response curves show that both N⁶ -benzyladenine and1-nitro-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine are active in thisbioassay.

FIG. I

Dose-response increase in rate of chlorophyll biosynthesis (absorbanceof leachate at 663 nm) obtained with N⁶ -benzyladenine and a compound ofthe invention 1-nitro-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine.

FIG. II

Dose-response increase in cotyledon surface area obtained with N⁶-benzyladenine and 1-nitro-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine.

ANALOG TEST RESULTS-CUCUMBER COTYLEDON BIOASSAY

Compounds with moderate to excellent activity are listed below, alongwith the concentration of the compound, in parts per million, which isrequired to achieve 50% of the maximum response.

    ______________________________________                                        CUCUMBER COTYLEDON BIOASSAY FOR CYTOKININS                                    Compound                   ED.sub.50, PPM                                     ______________________________________                                        1-Nitro-3-(α,α,α,4-tetrafluoro- .sub.-- m-tolyl)guanidin    e                          0.48                                               1-( .sub.-- m-Methoxybenzyl)-3-nitroguanidine                                                            1.8                                                1-(3,5-Dichlorophenyl)-3-nitroguanidine                                                                  0.125                                              1-Nitro-3-(α,α,α-trifluoro- .sub.-- m-tolyl)guanidine                                  0.125                                              1-Cyano-3-(α,α,α-trifluoro- .sub.-- m-tolyl)guanidine                                  0.22                                               1-Nitro-3-phenylguanidine  8.0                                                1-Benzyl-3-nitroguandine   5.7                                                1-( .sub.-- m-Chlorobenzyl)-3-nitroguanidine                                                             3.8                                                1-Cyano-3-(α,α,α,4-tetrafluoro- .sub.-- m-tolyl)guanidin    e                          2.5                                                1-( .sub.-- m-Methoxyphenyl)-3-nitroguanidine                                                            1.0                                                1-( .sub.-- m-Iodophenyl)-3-nitroguanidine                                                               0.125                                              1-( .sub.-- m-Bromophenyl)-3-nitroguanidine                                                              0.48                                               1-( .sub.-- m-Bromophenyl)-3-cyanoguanidine                                                              1.0                                                1-( .sub.-- m-Chlorophenyl)-3-nitroguanidine                                                             1.8                                                1-( .sub.-- m-Chlorophenyl)-3-cyanoguanidine                                                             1.8                                                1-( .sub.-- m-Fluorophenyl)-3-nitroguanidine                                                             8.0                                                1-Nitro-3- .sub.-- m-tolylguanidine                                                                      1.0                                                1-Cyano-3- .sub.-- m-tolylguanidine                                                                      1.0                                                1-Cyano-3-(α,α,α,trifluoro- .sub.-- m-tolyl)guanidine                                  0.22                                               1-( .sub.-- m-Methoxyphenyl)-3-nitroguanidine                                                            1.0                                                1-[ .sub.-- m-(Difluoromethoxy)-phenyl]-3-nitroguanidine                                                 0.06                                               1-Nitro-3-[ .sub.-- m-(trifluoromethoxy)phenyl]guanidine                                                 3.8                                                1-[ .sub.-- m-(Methylthio)phenyl]-3-nitroguanidine                                                       1.0                                                1-( .sub.-- m-Ethoxyphenyl)-3-nitroguanidine                                                             3.8                                                1-Nitro-3-[ .sub.-- m(1,1,2,2-tetrafluoroethoxy)phenyl]-guani-                                           0.48                                               dine                                                                          1-(α-Hydroxy- .sub.-- m-tolyl)-3-nitroguanidine                                                    2.5                                                1-(α-Methoxy- .sub.-- m-tolyl)-3-nitroguanidine                                                    1.8                                                1-Nitro-3-] .sub.-- m(2,2,2-trifluoro-1,1-dihydroxyethyl)phenyl]                                         0.48                                               guanidine                                                                     Methyl- .sub.-- m-(3-nitroguanidine)benzoate                                                             3.8                                                1-( .sub.-- m-Acetylphenyl)-3-nitroguanidine                                                             3.8                                                1-( .sub.-- m-Cyanophenyl)-3-nitroguanidine                                                              1.0                                                1-( .sub.-- m-Cyanophenyl)-3-cyanoguanidine                                                              8.0                                                1-[ .sub.-- m-(Cyanomethyl)-phenyl]3-nitroguanidine                                                      3.8                                                1-( .sub.-- m-Nitrophenyl)-3-nitroguanidine                                                              8.0                                                1-[ .sub.-- m-(Dimethylamino)-phenyl]-3-nitoguanidine                                                    3.8                                                1-Cyano-3-( .sub.-- m-methoxyphenyl)guanidine                                                            2.5                                                1-(3-Chloro-4-fluorophenyl)-3-nitroguanidine                                                             1.8                                                1-(3-Chloro-4-fluorophenyl)-3-cyanoguanidine                                                             14.0                                               1-(3,4-Dichlorophenyl)-3-nitroguanidine                                                                  1.0                                                1-(4-Bromo- .sub.-- m-tolyl)-3-nitroguanidine                                                            1.0                                                1-(4-Chloro- .sub.-- m-tolyl)-3-nitroguanidine                                                           1.8                                                1-(4-Fluoro- .sub.-- m-tolyl)-3-nitroguanidine                                                           3.8                                                1-Nitro-3-(3,4-xylyl)-guanidine                                                                          3.8                                                1-(4-Chloro-α,α,α-trifluoro- .sub.-- m-tolyl)-3-nitro-                                 1.0                                                guanidine                                                                     1-(3,5-Dibromophenyl)-3-nitroguanidine                                                                   0.125                                              1-(3,5-Dichlorophenyl)-3-nitroguanidine                                                                  0.125                                              1-(3,5-Dichlorophenyl)-1-methyl-3-nitroguanidine                                                         3.8                                                1-Cyano-3-(3,5-dichlorophenyl)guanidine                                                                  0.48                                               1-(3,5-Dimethoxyphenyl)-3-nitroguanidine                                                                 14.0                                               1-(5-Bromo- .sub.-- m-tolyl)-3-nitroguanidine                                                            0.48                                               1-Nitro-3-(3,5-xylyl)-guanidine                                                                          3.8                                                1-(α,α,α,α',α',α'-Hexafluoro)-3,5-xyly    l)-3-nitro-                3.8                                                guanidine                                                                     1-(2-Fluoro-3-methoxybenzyl)-3-nitroguanidine                                                            2.5                                                1-Nitro-3-(3,4,5-trichlorophenyl)guanidine                                                               3.8                                                1-(4-Chloro-α,α,α-trifluoro- .sub.-- m-tolyl)-3-cyano-                                 2.5                                                guanidine                                                                     1-( -o-Fluorobenzyl)-3-nitroguanidine                                                                    3.8                                                1-( .sub.-- m-Iodobenzyl)-3-nitroguanidine                                                               14.0                                               1-( .sub.-- m-Chlorobenzyl)-3-nitroguanidine                                                             3.8                                                1-( .sub.-- m-Bromobenzyl)-3-nitroguanidine                                                              5.7                                                1-( .sub.-- m-Fluorobenzyl)-3-nitroguanidine                                                             8.0                                                1-( .sub.-- m-Methylbenzyl)-3-nitroguanidine                                                             8.0                                                1-Cyano-3-( .sub.-- m-methylbenzyl)guanidine                                                             8.0                                                1-(Nitro-3-[ .sub.-- m-(trifluoromethyl)benzyl]guanidine                                                 8.0                                                1-( .sub.-- m-Methoxybenzyl)-3-nitroguanidine                                                            1.8                                                1-Cyano-3-( .sub.-- m-methoxybenzyl)guanidine                                                            2.5                                                1-( .sub.-- m-Hydroxybenzyl)-3-nitroguanidine                                                            1.0                                                1-( .sub.-- m-Ethoxybenzyl)-3-nitroguanidine                                                             8.0                                                1-Nitro-3-( .sub.-- m-propoxybenzyl)guanidine                                                            1.3                                                1-( .sub.-- m-sec-Butoxybenzyl)-3-nitroguanidine                                                         0.31                                               1-( -p-Fluorobenzyl)-3-nitroguanidine                                                                    8.0                                                1-Nitro-3-{m[(tetra-hydro-2H--pyran-2-yl)oxy]-                                                           1.0                                                benzyl}guanidine                                                              1-(2,5-Difluorobenzyl)-3-nitroguanidine                                                                  5.7                                                1-(2-Fluoro-5-methoxybenzyl)-3-nitroguanidine                                                            2.5                                                1-(2-Fluoro-5-methylbenzyl)-3-nitroguanidine                                                             8.0                                                1-(2,4-Difluorobenzyl)-3-nitroguanidine                                                                  10.6                                               1-(2,4-Dichlorobenzyl)-3-nitroguanidine                                                                  8.0                                                1-(α-Methylbenzyl)-3-nitroguanidine                                                                1.8                                                1-( .sub.-- m-α-Dimethylbenzyl)-3-nitroguanidine                                                   14.0                                               1-( -o-Fluorophenethyl)-3-nitroguanidine                                                                 14.0                                               1-( .sub.-- m-Methoxyphenethyl)-3-nitroguanidine                                                         14.0                                               1-Nitro-3-[α-(trifluoro-methyl)benzyl]guanidine                                                    2.5                                                1-(α-Ethylbenzyl)-3-nitroguanidine                                                                 0.22                                               ______________________________________                                    

EXAMPLE 6 Tissue culture test to establish cytokinin mode of action

Cytokinins are involved with plant cell division. To specifically testfor cytokinin-like activity of an unknown compound, said compounds mustbe able to substitute for a known cytokinin by allowing acytokinin-dependent tissue culture to grow on a defined medium. Calluscultures derived from cotyledon tissue of soybeans (variety Acme)require a cytokinin in order to grow on agar media. These calluscultures are used in this evaluation to determine whether the compoundsof the invention promote cell division.

Callus is prepared by subculturing on a basal medium containingvitamins, mineral salts, 3% sucrose, 0.9% agar, and naphthalene aceticacid at 2 ppm (PNAS 54:1052-8 (1965)). The addition of 10⁻⁷ M N⁶-benzyladenine is normally required for callus to grow. Test media isprepared by omitting the known cytokinin (N⁶ -BA) and substituting testcompounds at various concentrations. Four replicate dishes are used pertest solution. Into 15×60 mm plastic Petri dishes is poured 6 ml of agarmedia containing test compounds. Callus is scraped from subcultureplates, gently broken into small pieces and mixed with dilute agar inbasal medium. Then, 2 ml of this is layered onto each test medium. Aftereight days at 25° C., in the dark, the dishes are examined for growth ofthe callus on the various test media. The data obtained are reported inTable IV below.

                  TABLE IV                                                        ______________________________________                                        GROWTH PROMOTION OF A CYTOKININ-DEPENDENT                                     TISSUE CULTURE ON A DEFINED MEDIUM                                                          Concentration                                                                              Percent of Callus.sup.a                            Compound      (PPM)        Which Is Growing                                   ______________________________________                                        Untreated control                                                                           0             0.3                                               1-(3,5-Dichloro-                                                                            0.1           4.0                                               phenyl)-3-nitro-                                                                            0.3          100.0                                              guanidine     1.0          100.0                                              1-Nitro-3-(α,α,α,4-                                                       0.3           8.0                                               tetrafluoro- .sub.-- m-tolyl)-                                                              1.0          100.0                                              guanidine     3.0          100.0                                                            10.0         100.0                                              1-( .sub.-- m-Methoxybenzyl)-                                                               3.0           15.0                                              3-nitroguanidine                                                                            10.0         100.0                                                            30.0         100.0                                                            100.0        100.0                                              N.sup.6 --benzyladenine                                                                     10.sup.-7 M  100.0                                              ______________________________________                                         .sup.a Growth is measured visually by comparing small brown cell clusters     (not growing) to those which are large and white (growing).              

It is seen that the compounds of the present invention do replace N⁶-benzyladenine, thereby, indicating cytokinin-like activity.

EXAMPLE 7 Antisenescence properties on disks of leaf lettuce

Leaf disks are prepared from locally-purchased Romaine lettuce. Thedisks (4 per treatment) are placed in Petri dishes containing Whatman #1filter papers and test solutions containing 10 ppm of test compound(with 0.2% acetone) or 100 ppm of test compound (with 2% acetone) in H₂O. After five days at room temperature in the dark, the disks areextracted with dimethylformamide, and absorbance of chlorophyll ismeasured at A 663 nm. Data obtained are reported in Table V.

                  TABLE V                                                         ______________________________________                                        ANTISENESCENCE PROPERTIES OF TEST COMPOUNDS                                   APPLIED TO LEAF DISKS OF LEAF LETTUCE                                                        Concen-  Percent Increase In                                                  tration  Chlorophyl Retention                                  Treatment      (PPM)    Over Untreated Controls                               ______________________________________                                         .sub.-- m-Triflurormethyl-                                                                  100      18                                                    phenyldicyandiamide                                                           1-Benzyl-3-nitro-                                                                            10       18                                                    guanidine      100      17                                                    1-Nitro-3-(α,α,α-tri-                                                      100      16                                                    fluoro- .sub.-- m-tolyl)guanidine                                             1-(3,5-Dichlorophenyl)-                                                                      10       14                                                    3-nitroguanidine                                                              1-Nitro-3-(α,α,α,4-tetra-                                                  10       40                                                    fluoro- .sub.-- m-tolyl)guanidine                                             1-( .sub.-- m-Methoxybenzyl)-3-                                                              10       11                                                    nitroguanidine 100      15                                                    1-Cyano-3-(α,α,α,4-tetra-                                                  10       33                                                    fluoro- .sub.-- m-tolyl)guanidine                                                            100      17                                                    1-( .sub.-- m-Methoxyphenyl)-3-                                                              10       17                                                    nitroguanidine 100      34                                                    1-Cyano-3-( .sub.-- m-Methoxy-                                                               10       40                                                    benzyl)guanidine                                                                             100      26                                                    1-Nitro-3-[ .sub.-- m-(trifluoro-                                                            10       26                                                    methyl)benzyl]guanidine                                                       1-Nitro-3-phenylguanidine                                                                    10       10                                                    ______________________________________                                    

Lettuce leaf disks treated with the present compounds enhancechlorophyll retention about 10% to 40% over untreated controls.

EXAMPLE 8 Enlargement of leaf disks of lima bean

In this evaluation, lima beam leaf disks are found to respond to variouscompounds of this invention by increasing the growth of the disks whenexposed to aqueous solutions of test compounds. Five or six leaf disks(combined area of 2.2 sq. cm) are placed in 15×100 mm Petri dishes withthree layers of Whatman #1 filter paper and 12 ml of 40 mM KCl, plusvarious concentrations of test compounds. The dishes are kept in thelight for six days, then disk area is measured with an area meter.Several of the test compounds are found to increase the amount of growthexhibited by the lima beam leaf disks. These data are reported in TableVI below.

                  TABLE VI                                                        ______________________________________                                        ENHANCED ENLARGEMENT OF LEAF                                                  DISKS OF LIMA BEANS                                                                         Concentration                                                                              Percent Increase                                   Treatment     (PPM)        in Leaf Disk Area                                  ______________________________________                                        Control       0            54                                                 1-( .sub.-- m-Methoxyphenyl)-                                                               0.12         87                                                 3-nitroguanidine                                                                            1.0          103                                                1-Nitro-3-(α,α,α,4-                                                       1.0          92                                                 tetrafluoro- .sub.-- m-tolyl)-                                                              8.0          107                                                guanidine                                                                     ______________________________________                                    

EXAMPLE 9 Determination of growth-promoting effects of nitroguanidinesand cyanoguanidines on radish seedlings in liquid culture

In this evaluation, surface-sterilized radish seeds, variety CherryBelle, are asceptically placed in 125 ml Erlenmeyer flasks containing 20ml autoclaved medium. The medium contains distilled water, mineral saltssuch as those used for plant tissue cultures (300 mg/l KH₂ PO₄, 65 mg/lKCl, 4.9 mg/l MnSO₄.H₂ O; 2.7 mg/l ZnSO₄ ; 7H₂ O; 1.8 mg/l H₃ BO₃ ; 0.8mg/l; 0.35 mg/l.CuSO₄.5H₂ O; 0.1 mg/l (NH₄)₆ MO₇ O₂₄.4H₂ O; 499 mg/lCa(NO₃)₂.O4H₂ O; 1 g/l KNO₃ ; 1 g/l NH₄ NO₃ ; 71 mg/l MgSO₄.7H₂ O; and42 mg/l commercial 10% iron chelate), and an appropriate dilution oftest compound prepared from a stock solution of 5000 ppm (technicalcompound) in acetone. The medium pH is adjusted to 5.8 beforeautoclaving, and the test compound is added after autoclaving of themedium, just prior to adding the 10 to 20 seeds per flask. Flasks areincubated on a reciprocating shaker for six days under dim fluorescentlight at room temperature. At this time, seedlings are removed, blotted,and dissected into various organs which are weighed (fresh weight)and/or assessed for chlorophyll content.

Data obtained are reported in Table VII.

                  TABLE VII                                                       ______________________________________                                        GROWTH PROMOTING EFFECTS OF NITRO-                                            GUANIDINES AND CYANOGUANIDINES ON                                             RADISH SEEDLINGS                                                                           Con-      Percent Change In Fresh                                             centration                                                                              Weight of Radish Cotyledons                            Treatment    (PPM)     Over Untreated Controls                                ______________________________________                                        Untreated controls                                                                         0         --                                                     1-(3,5-Dichloro-                                                                           0.001      -4                                                    phenyl)-3-nitro-                                                                           0.003      -4                                                    guanidine    0.01      +24                                                                 0.03      +64                                                                 0.1       +92                                                                 0.3       +151                                                   ______________________________________                                    

It can be seen that there is a 20% to 150% increase in radish cotyledonweights in comparison to untreated controls when 0.01 to 0.5 ppm1-(3,5-dichlorophenyl)-3-nitroguanidine is used to treat said radishcotyledons.

EXAMPLE 10 Early increase in development of tubers of potato, Solanumtuberosum, variety Superior

In greenhouse tests, young potato plants whose roots have been exposedto test compounds of the invention via hydroponic treatment for 48 hourshave larger tubers early in tuber development than do untreated plants.This suggests that under field conditions, treated plants could producemore tubers that would reach the status of U.S. No. 1's.

In these tests, potato plants, variety Superior, are grown invermiculite until they are 7 cm tall. They are then treatedhydroponically with aqueous solutions of test compound at variousconcentrations for 48 hours. Thereafter, the potato plants are plantedin greenhouse soil and grown for two months before evaluation. Fourplants are used per treatment. In plants treated with test compounds,more tubers with weights above 2 oz. are in evidence early in tuberdevelopment. In untreated plants, 20% (w/w) of the young tubers are inthis weight class while in treated plants, 29 to 81% (w/w) of the tubersare in this class. For perspective, the tubers weighing over 2 oz. haveprobably reached 40 to 60% of their expected weight, were they to becomeU.S. #1's.

Data obtained are reported in Table VIII below.

                                      TABLE VIII                                  __________________________________________________________________________    EARLY INCREASE IN SIZE OF                                                     DEVELOPING TUBERS OF POTATO, VARIETY SUPERIOR                                             Tubers Weighing Over 2 oz. (55 g)                                                            Percent Increase                                               Concentration                                                                         Total Weight                                                                         Over Untreated                                                                         Percent of Total                          Treatment   (PPM)   (g)    Controls Tuber Weight                              __________________________________________________________________________    Untreated control                                                                         0        77     0       20                                        1-(3,5-Dichlorophenyl)-                                                                   0.1     175    127      52                                        3-nitroguanidine                                                                          1.0     240    217      57                                        1-Nitro-3-(α,α,α-tri-                                                   0.1     102     32      29                                        fluoro- --m-tolyl)guanidine                                                               1.0     140     82      41                                                    10.0    419    184      81                                        1-( --m-Methoxybenzyl)-                                                                   1.0     107     39      32                                        3-nitroguanidine                                                                          10.0    108     40      29                                                    100.0   182    136      64                                        __________________________________________________________________________

EXAMPLE 11 Evaluation of test compounds for inhibiting lodging of paddyrice

In this evaluation, IR-36 paddy rice is transplanted into 12 m² plots infour replicates at the rate of three seedlings per hill. Hill spacing is25×25 cm. A basal application of fertilizer N,P,K at 60, 40, and 40kg/ha is made and followed by an additional application of nitrogen (30kg/ha) 30 and 50 days after the plots are sprayed with anaqueous-acetone mixture (20/80) of test compound containing 0.25% of anonionic wetting agent (i.e., nonylphenol containing 9 mols of ethyleneoxide, oleic acid, and isopropanol). Application of test compound ismade at the panicle development stage approximately equivalent toZadok's stage Z31/32. These evaluations are conducted in an area wherelodging pressure is normally severe. During the growing season, water ismaintained in the paddies at a depth of about 3 to 5 cm. Four monthsafter transplanting, the plots are examined, and the rice harvested from6 m² sampling areas. Data obtained are reported below.

    ______________________________________                                                         Concentration                                                                             Percent                                          Treatment        kg/ha       Lodging                                          ______________________________________                                        Untreated control                                                                              0           100                                              1-(3,5-Dichlorophenyl)-                                                                        1           20                                               3-nitroguanidine 2           10                                                                4            5                                               ______________________________________                                    

EXAMPLE 12 Evaluation of test compounds for increasing yield in paddyrice

The procedure of Example 11 is repeated except that the aqueous-acetonemixture containing test compound is applied to transplanted IR-36 paddyrice when it reaches the maximum tillering stage. Also, theaqueous-acetone (20/80) mixture containing test compound and nonionicwetting agent is applied to the tillered rice at rates sufficient toprovide 11, 33, or 100 g/ha of test compound. About four months aftertransplanting, the rice is harvested, with the resultant data reportedbelow.

    ______________________________________                                        RICE YIELD ENHANCEMENT                                                                                        Yield                                                       Rate      Yield,* Percent                                       Treatment     g/ha      Ton/ha  of Control                                    ______________________________________                                        Untreated control                                                                           --        4.46    100                                           1-Potassium-3-(3,5-                                                                         11        5.21    117                                           dichlorophenyl)-1-                                                                          33        4.70    105                                           nitroguanidine                                                                              100       4.58    103                                           ______________________________________                                         *at 14% moisture                                                         

EXAMPLE 13 Evaluation of test compounds for increasing grain yield inwheat and barley

Surprisingly, it is also noted that these compounds are effective forinducing early maturation of grains such as wheat and barley.

During the third week of May, fields previously plowed, harrowed, andfertilized with 896 kilograms/hectare of a 9:9:9 chemical fertilizer areseeded in one section with 2.44 hectoliters/hectare of Spring wheat(variety Sinton).

In another section, the field is seeded with 2.09 hectoliters/hectare ofSpring barley (variety Herta). Each field is staked out in 12 squaremeter plots. When the plants reach the Z30/Z31 Zodak's stage, the plotsare then sprayed with an 80:20 acetone/water mixture containing 0.25% ofa nonionic wetting agent (i.e., nonylphenol containing 9 mols ofethylene oxide, oleic acid, and isopropanol) and a sufficient amount oftest compound to provide 0 (untreated control), 0.22, 0.67, or 2.0 kg/haof said test compound. Each treatment is replicated five times. Sevenweeks after planting, the plots are harvested. The harvested grain isthen normalized to 15% moisture content and weighed. Data obtained arereported in Table IX below.

                  TABLE IX                                                        ______________________________________                                        EVALUATION OF TEST COMPOUNDS FOR INCREASING                                   GRAIN YIELD IN WHEAT AND BARLEY                                                                  Grain Yield                                                                             Hecto-                                                              Rate      liters/Hec-                                                                           Percent of                               Compound   Crop    Kg/ha     tare    Control                                  ______________________________________                                        1-(3,5-Dichloro-                                                                         Spring  0 (control)                                                                             25.84   --                                       phenyl)-3-nitro-                                                                         Wheat   0.22      29.84   115                                      guanidine          0.67      30.80   119                                                         2.0       29.32   113                                      1-(3,5-Dichloro-                                                                         Spring  0 (control)                                                                             22.62   --                                       phenyl)-2-methyl-                                                                        Wheat   0.22      25.14   111                                      3-nitro-guanidine  0.67      26.19   116                                                         2.0       24.80   110                                      1-(3,5-Dichloro-                                                                         Spring  0 (control)                                                                             30.10   --                                       phenyl)-3-nitro-                                                                         Barley  0.22      32.90   108                                      guanidine          0.67      33.20   109                                                         2.0       34.80   114                                      ______________________________________                                    

EXAMPLE 14 Evaluation of test compounds as yield-enhancing agents forcotton (Gossypium hirsutum cv Acala)

In this evaluation, a field, previously plowed, harrowed, andfertilized, is seeded with cotton (Gossypium hirsutum cv Acala) duringthe third week of April. Plantings are made to provide approximately onemeter spacing between rows and an average of about 12 plants per meter.Each plot is four meters in length, and three replicates per treatmentare used. Four weeks after planting, when the cotton plants have reachedthe two- to three-leaf stage, the plants are sprayed with a 50:50acetone/water mixture containing 0.25% of a nonionic, modified phthalicglycerol alkyl resin, emulsifier-spreader, and a sufficient amount oftest compound to provide 0.0 (untreated control), 0.062, 0.125, or 0.25kg/ha of test compound. About seven weeks after planting, when thecotton plants have reached the stage of first flowering, different plots(previously untreated), but in the same field, are sprayed withsolutions of test compound prepared as described above. All plants arethen permitted to grow to maturity using normal cultural practices.During the second week of October, the cotton from each plot is handharvested, and the weight of the seed cotton determined for each plot.The results obtained from all treatments are reported in Tables X and XIbelow as the average weight in kg/ha of seed cotton obtained from thethree replicates of each treatment.

                  TABLE X                                                         ______________________________________                                        EVALUATION OF 1-NITRO-3-(α,α,α,4-TETRAFLUORO- .sub.--       m-                                                                            TOLYL)GUANIDINE FOR YIELD                                                     ENHANCEMENT OF COTTON                                                                                  Average Yield                                        Time of       Rate       of Seed Cotton                                       Application   kg/ha      (kg)/Plot                                            ______________________________________                                        2-3 leaf      0.0 (control)                                                                            1.57                                                               0.062      1.72                                                 2-3 leaf      0.0 (control)                                                                            1.70                                                               0.125      1.85                                                 2-3 leaf      0.0 (control)                                                                            1.97                                                               0.25       2.22                                                 First flowering                                                                             0.0 (control)                                                                            1.73                                                               0.062      2.25                                                 First flowering                                                                             0.0 (control)                                                                            1.61                                                               0.125      2.20                                                 First flowering                                                                             0.0 (control)                                                                            1.85                                                               0.25       2.45                                                 ______________________________________                                    

EXAMPLE 15 Evaluation of test compounds to determine their efficacy forincreasing the number of U.S. No. 1 potatoes and the total weight ofpotatoes produced per plant

In this evaluation, white potatoes (Solanum tuberosum Superior) (2016kg/ha) are planted during the first week of April. Approximately fiveweeks after planting, when more than 80% of the potato plants haveemerged, plots comprising two 9.6 meter rows, spaced 0.9 meters apart,are sprayed with a 50:50 acetone/water mixture containing 0.25% byweight of a modified phthalic glycerol alkyl resin, nonionicemulsifier-spreader, and sufficient test compound to provide 0.0(untreated control), 0.25, 0.50, or 1.0 kg/ha of test compound. Sixreplicates per treatment are used. At one-week intervals, additionalplots are sprayed in the same manner and at the same rates as describedabove.

The treated plants are cared for in accordance with normal culturalpractices utilized in the growing of potatoes. When said plants reachmaturity, about 20 weeks after planting, they are harvested. The totalnumber of U.S. No. 1 potatoes per plot and total weight of all potatoesper plot are determined. Data obtained are reported in Tables XI and XIIbelow.

                                      TABLE XI                                    __________________________________________________________________________    EVALUATION OF TEST COMPOUNDS FOR                                              INCREASING THE NUMBER OF U.S. NO. 1 POTATOES                                  PER PLANT USING WHITE POTATOES                                                (SOLANUM TUBEROSUM CV. SUPERIOR)                                                                 % (±) Untreated Control                                               Rate of U.S. No. 1 Potatoes                                     Compound      kg/ha                                                                              E 1                                                                              E 2 E 3                                                 __________________________________________________________________________    1-Nitro-3-(α,α,α,4-tetrafluoro                                            1.0  +21                                                                              +27 +15                                                  .sub.--m-tolyl)guanidine                                                                   0.50 +23                                                                              +28 +14                                                               0.25 +21                                                                              +30 +19                                                 1-(3-Chloro-4-fluorophenyl)-                                                                1.0  +19                                                                              +24 +19                                                 3-nitroguanidine                                                                            0.50 +25                                                                              +20 +7                                                                0.25 +21                                                                              +24 +14                                                 1-( .sub.--m-Methoxybenzyl)-3-                                                              1.0  +10                                                                              +36 +19                                                 nitroguanidine                                                                              0.50 +18                                                                              +32 +20                                                               0.25 +23                                                                              +34 +18                                                 1-(3,5-Dichlorophenyl-3-                                                                    1.0  +12                                                                              +38 +13                                                 nitroguanidine                                                                              0.50 +14                                                                              +35 +8                                                                0.25 +15                                                                              +34 +10                                                 __________________________________________________________________________     E1, E2, E3 = Application of test compound one, two, or three weeks after      plant emergence of the potato plants.                                         (±) =  Increase or decrease over untreated controls.                  

                  TABLE XII                                                       ______________________________________                                        EVALUATION OF TEST COMPOUNDS FOR                                              INCREASING THE TOTAL WEIGHT OF POTATOES                                       ( SOLANUM TUBEROSUM SUPERIOR) [WHITE                                          POTATOES] COMPARED TO UNTREATED CONTROLS                                      YIELDING 188 POUND/PLOT (380 CWT/ACRE, 42.6                                   METRIC TONS/HA) OF SAID POTATOES                                                                   Total Potato Yield                                                            Per Treatment % (±)                                                  Rate  Untreated Control                                        Compound         kg/ha   E 1     E 2   E 3                                    ______________________________________                                        1-Nitro-3-(α,α,α,4-tetrafluoro-                                              1.0     +17     +23   +13                                     .sub.--m-tolyl)nitroguanidine                                                                 0.50    +19     +24   +12                                                     0.25    +18     +26   +16                                    1-(3-Chloro-4-florophenyl)-                                                                    1.0     +15     +20   +17                                    3-nitroguanidine 0.50    +21     +16   +5                                                      0.25    +18     +20   +11                                    1-( .sub.--m-Methoxybenzyl)-                                                                   1.0      +7     +25   +16                                    3-nitroguanidine 0.50    +15     +38   +17                                                     0.25    +20     +30   +14                                    1-(3,5-Dichlorophenyl)-                                                                        1.0     +11     +32   +11                                    3-nitroguanidine 0.50    +12     +30    +6                                                     0.25     +9     +28    +7                                    ______________________________________                                         E1, E2, and E3 indicate the time of application of test compound one, two     or three weeks, respectively, after emergence of the potato plants.           (±) = Increase or decrease over untreated controls.                   

EXAMPLE 16 Evaluation of test compounds to determine their efficacy forincreasing the total weight of potatoes produced

The procedure of Example 15 is repeated except that a variety ofcompounds is evaluated. The compounds are applied two weeks after theseedling plants have emerged, at application rates from 0.25 kg/ha to2.0 kg/ha. The potatoes are harvested about 20 weeks after planting, anddata obtained are reported in Table XIII below where the total freshweight of potatoes from treated plots is compared with the total freshweight of potatoes obtained from untreated plots. The same procedure asdescribed above is employed except that the test compounds are preparedas a 30% liquid flowable formulation which is dispersed in water andapplied as an aqueous spray. Data obtained with these flowableformulations is reported in Table XIII-A.

The flowable concentrates used in this evaluation comprise:

    ______________________________________                                                             Percent W/W                                              ______________________________________                                        Test compound (90% pure)                                                                             30.00                                                  Colloidal magnesium aluminum silicate                                                                0.40                                                   Sodium salts of polymerized alkyl                                                                    1.50                                                   naphthalene sulfonic acids                                                    Propylene glycol/dipropylene glycol                                                                  8.00                                                   Ethoxylated octylphenol                                                                              0.10                                                   Nonylphenoxy polyethoxyethanol                                                                       0.10                                                   Citric acid            0.07                                                   Xanthan gum            0.06                                                   Paraformaldehyde       0.10                                                   Tap water              59.67                                                                         100.00                                                 ______________________________________                                    

                  TABLE XIII                                                      ______________________________________                                        EVALUATION OF TEST COMPOUNDS TO DETERMINE                                     THEIR EFFICACY FOR INCREASING THE TOTAL                                       WEIGHT OF POTATOES PRODUCED                                                                            Total Tuber Fresh                                                     Rate    Weight Percent (±)                                Treatment        kg/ha   Untreated Controls                                   ______________________________________                                        Untreated controls                                                                             --      151 cwt/A*                                           1-Benzyl-3-nitroguanidine                                                                      2.0     +12                                                                   0.5     +13                                                  1-Nitro-3-(α,α,α-trifluoro-                                                  0.5      +9                                                   .sub.-- m-tolyl)guanidine                                                    1-( .sub.-- m-acetylphenyl)-3-                                                                 1.0     +18                                                  nitroguanidine    0.25    +6                                                  1-( .sub.-- m-Methoxyphenethyl)-                                                               2.0      +5                                                  3-nitroguanidine 0.5     +10                                                  1-(4-Chloro- .sub.-- m-tolyl)-                                                                 0.5      +4                                                  3-nitroguanidine                                                              1-( .sub.-- m-Methoxyphenyl)-                                                                  0.5      +3                                                  3-nitroguanidine                                                              1-( .sub.-- m-Fluorobenzyl)-                                                                   2.0      +6                                                  3-nitroguanidine                                                              1-( .sub.-- m-Bromophenyl)-                                                                    2.0      +2                                                  3-nitroguanidine 0.5     +17                                                  1-Nitro-3-(3,4-xylyl)-                                                                         0.5      +3                                                  guanidine                                                                     1-[ .sub.-- m-(Difluoromethoxy)-                                                               2.0      +2                                                  phenyl]-3-nitroguanidine                                                                       0.5     +20                                                  1-Nitro-3-( .sub.-- m-propoxy-                                                                 2.0     +25                                                  benzyl)guanidine                                                              1-(α-Methylbenzyl)-                                                                      2.0      +9                                                  3-nitroguanidine 0.5     +16                                                  ______________________________________                                          *Cwt/A = Hundred weight per acre                                        

                  TABLE XIII-A                                                    ______________________________________                                        EVALUATION OF TEST COMPOUNDS FORMULATED AS                                    FLOWABLE CONCENTRATES TO DETERMINE THEIR                                      EFFICACY FOR INCREASING THE TOTAL WEIGHT                                      OF POTATOES PRODUCED                                                                                   Total Tuber Fresh                                                     Rate    Weight Percent (±)                                Treatment        kg/ha   Untreated Controls                                   ______________________________________                                        1-Nitro-3-(α,α,α-tri-                                                        0.5     +11                                                  fluoro- .sub.-- m-tolyl)guanidine                                                              0.25    +11                                                                   0.125   +11                                                  1-(3,5-Dichlorophenyl)-                                                                        0.5     +8                                                   3-nitroguanidine 0.25    +8                                                                    0.125   +11                                                  1-Nitro-3-(α,α,α,4-                                                          0.5     +8                                                   tetrafluoro- .sub.-- m-tolyl)-                                                                 0.25    +8                                                   guanidine        0.125   +4                                                   1-( .sub.-- m-Methoxybenzyl)-                                                                  0.5     +6                                                   3-nitroguanidine 0.25    +13                                                                   0.125   +5                                                   ______________________________________                                         Untreated control average total yield 202 cwt/A.                         

EXAMPLE 17 Evaluation of test compounds to determine their efficacy forincreasing the total weight of Kennebec variety potatoes produced

The procedure of Example 15 is again repeated except that Kennebecvariety potatoes are used for the evaluations. Test compounds areapplied as aqueous/acetone mixtures per Example 15 but at ratessufficient to provide from 0.5 kg/ha to 2.0 kg/ha. The potatoes areharvested at maturity, about 20 weeks after planting, and data obtainedare reported in Table XIV. Data are reported as total fresh weight ofpotatoes compared with the total fresh weight of potatoes obtained fromuntreated controls.

                  TABLE XIV                                                       ______________________________________                                        EVALUATION OF TEST COMPOUNDS TO DETERMINE                                     THEIR EFFICACY FOR INCREASING THE TOTAL                                       WEIGHT OF KENNEBEC VARIETY POTATOES                                                                    Total Tuber Fresh                                                     Rate    Weight Percent (±)                                Treatment        kg/ha   Untreated Controls                                   ______________________________________                                        1-Cyano-3-(α,α,α-tri-                                                        2.0     +14                                                  fluoro- .sub.-- m-tolyl)guanidine                                                              0.5     +7                                                   1-Benzyl-3-cyanoguanidine                                                                      0.5     +16                                                  1-( .sub.-- m-Chlorophenyl)-3-                                                                 2.0     +9                                                   nitroguandine                                                                 1-Nitro-3-(3,5-xylyl)-                                                                         2.0     +9                                                   guanidine                                                                     1-( .sub.-- m-Methoxybenzyl)-3-                                                                2.0     +15                                                  nitroguanidine   0.5     +6                                                   1-( .sub.-- m-Methylbenzyl)-3-                                                                 2.0     +6                                                   nitroguanidine                                                                1-Cyano-3-( .sub.-- m-Methoxy-                                                                 2.0     +5                                                   benzyl)guanidine                                                              1-( -p-Fluorobenzyl)-3-                                                                        2.0     +8                                                   nitroguanidine   0.5     +4                                                   ______________________________________                                    

EXAMPLE 18 Evaluation of test compounds for increasing total potatoyield and increasing production of U.S. No. 1 potatoes on differentpotato varieties

The procedure of Example 15 is employed with the following exceptions:(1) test compounds are applied at two rates, 0.25 and 1.0 kg/ha, (2)several different varieties of white potatoes (Solanum tuberosum) areused, and (3) the compounds are applied one or two weeks after thepotato plants have emerged from the soil. The several varieties ofpotatoes employed in this evaluation are Katahdin, Kennebec, Norchip,and Superior.

Data obtained are reported in Table XV below.

                  TABLE XV                                                        ______________________________________                                        EVALUATION OF TEST COMPOUNDS FOR                                              INCREASING THE TOTAL WEIGHT OF POTATOES AND                                   THE NUMBER OF U.S. NO. 1 POTATOES                                             PRODUCED PER PLANT                                                                           Tuber Fresh Weight %                                                          (±) Untreated Controls                                                     E 1       E 2                                                               Rate    U.S.          U.S.                                       Compound     kg/ha   No. 1   Total No. 1 Total                                ______________________________________                                                       VARIETY KATAHDIN                                               1-Nitro-3-(α,α,α,4-                                                      1.0     +13     +14   +12   +15                                  tetrafluoro- .sub.--m-                                                                     0.25    +13     +12   +15   +18                                  tolyl)guanidine                                                               1-( .sub.--m-Methoxybenzyl)-                                                               1.0     +21     +21   +11   +13                                  3-nitroguanidine                                                                           0.25    +18     +18    +4    +6                                  Untreated controls: Average yield - 207 cwt/A, U.S. No. 1; 232 cwt/A          total.                                                                                       VARIETY KENNEBEC                                               1-Nitro-3-(α,α,α,4-                                                      1.0     -11      -8   +16   +17                                  tetrafluoro- .sub.--m-                                                                     0.25     +6      +5    +9   +10                                  nitroguanidine                                                                1-( .sub.--m-Methoxybenzyl)-                                                               1.0      -3       -2   +3    +4                                  3-nitroguanidine                                                                           0.25      0      +1    +4    +6                                  Untreated controls: Average yield - 257 cwt/A, U.S. No. 1; 307 cwt/A          total.                                                                                       VARIETY NORCHIP                                                1-Nitro-3-(α,α,α4-                                                       1.0     +12     +11    +1    +4                                  tetrafluoro- .sub.--m-                                                                     0.25     +7      +7    +7    +7                                  tolyl)guanidine                                                               1-( .sub.--m-Methoxybenzyl)-                                                               1.0      +7      +7    +3    +5                                  3-nitroguanidine                                                              Untreated controls: Average yield - 283 cwt/A, U.S. No. 1; 322 cwt/A          total.                                                                                       VARIETY SUPERIOR                                               1-Nitro-3-(α,α,α,4-                                                      1.0     +16     +14   +19   +19                                  tetrafluoro- .sub.--m-                                                                     0.25    +14     +14   +22   +21                                  tolyl)guanidine                                                               1-( .sub.--m-Methoxybenzyl)-                                                               1.0     +14     +13   +16   +14                                  3-nitroguanidine                                                                           0.25    +17     +15   +27   +22                                  Untreated controls: Average yield - 283 cwt/A, U.S. No. 1; 322 cwt/A          total.                                                                        ______________________________________                                         E 1 = Test compound applied one week after emergence of potato plants.        E 2 = Test compound applied two weeks after emergence of potato plants.       Cwt/A = Hundred weight per acre.                                              (±) = Increase or decrease over untreated controls.                   

EXAMPLE 19 Evaluation of test compounds for increasing total freshweight of potatoes (Solanum tuberosum Superior)

The procedure of Example 15 is repeated except that a variety ofcompounds is evaluated at rates of from 0.125 kg/ha to 1.0 kg/ha, andthe 50/50 aqueous/acetone mixture containing 0.25% of the nonionicsurfactant and the test compound is applied to the potato plants threeweeks after they have emerged from the soil.

The potatoes are harvested about 20 weeks after planting, and the totalweight of potatoes from treated plants is compared to the total weightof potatoes from the untreated controls. Data obtained are reported inTable XVI below.

                  TABLE XVI                                                       ______________________________________                                        EVALUATION OF TEST COMPOUNDS APPLIED THREE                                    WEEKS AFTER EMERGENCE OF THE POTATO PLANTS                                    (VARIETY SUPERIOR)                                                                          Rate    Total Tuber Fresh Weight                                Compound      kg/ha   % (±) Untreated Controls                             ______________________________________                                        1-Benzyl-3-   1.0     +9                                                      nitroguanidine                                                                              0.5     +8                                                                    0.25    +5                                                                    0.125   +2                                                      Untreated controls average total yield: 402 cwt/A                             1-Nitro-3-(α,α,α-                                                         1.0     +11                                                     trifluoro- .sub.-- m-tolyl)-                                                                0.5     +15                                                     guanidine     0.25    +9                                                                    0.125   +1                                                      Untreated controls average total yield: 389 cwt/A                             1-Cyano-3-(α,α,α-                                                         1.0     +7                                                      trifluoro- .sub.-- m-tolyl)-                                                                0.5     +2                                                      guanidine     0.25    -5                                                                    0.125   -4                                                      Untreated controls average total yield: 398 cwt/A                             1-( .sub.-- m-chlorophenyl)-                                                                1.0     +10                                                     3-nitroguanidine                                                                            0.5     +6                                                                    0.25    +3                                                                    0.125   +7                                                      Untreated controls average total yield: 392 cwt/A                             1-(4-Chloro-α,α,α-                                                        1.0     +10                                                     trifluoro- .sub.-- m-tolyl)-                                                                0.5     +5                                                      3-nitroguanidine                                                                            0.25    +8                                                                    0.125   + 6                                                     Untreated controls average total yield: 391 cwt/A                             1-(4-Bromo- .sub.-- m-tolyl)-                                                               1.0     +2                                                      3-nitroguanidine                                                                            0.5     +4                                                                    0.25    +4                                                                    0.125   +6                                                      Untreated controls average total yield: 410 cwt/A                             1-(3-Chloro-4-                                                                              1.0     +8                                                      fluorophenyl)-3-                                                                            0.5     +6                                                      nitroguanidine                                                                              0.25    +5                                                                    0.125    0                                                      Untreated controls average total yield: 412 cwt/A                             ______________________________________                                         Cwt/A = Hundred Weight/Acre.                                                  (±) = Increase or decrease over untreated controls.                   

EXAMPLE 20 Evaluation of test compounds for increasing the total potatoyield and the number of U.S. No. 1 potatoes per plant using whitepotatoes (Solanum tuberosum Superior)

The procedures of Example 15 is repeated except that test compounds areapplied at rates of from 0.0625 kg/ha to 1.0 kg/ha three weeks afterplanting, two weeks pre-emergence or three weeks post-emergence. Thetest compounds are applied in 50/50 aqueous/acetone mixture containing0.25% of the nonionic surfactant and sufficient test compound to providefrom 0.0625 kg/ha to 1.0 kg/ha. The potatoes are harvested when theyreach maturity, about 20 weeks after planting.

Data obtained are reported in Table XVII below.

                  TABLE XVII                                                      ______________________________________                                        EVALUATION OF TEST COMPOUND FOR INCREASING                                    THE TOTAL WEIGHT OF POTATOES AND THE NUMBER                                   OF U.S. NO. 1 POTATOES PRODUCED PER PLANT                                     WHEN THE TEST COMPOUND IS APPLIED THREE                                       WEEKS POST PLANTING - TWO WEEKS PRE-EMERGENCE                                                        Tuber Fresh                                                                   Weight %                                                                      (±) Untreated                                                              Controls                                                                    Rate    U.S.                                             Compound             kg/ha   No. 1   Total                                    ______________________________________                                        1-(3,5-Dichlorophenyl)-3-nitroguanidine                                                            1.0     +13     +14                                                           0.5     +7      +8                                                            0.25    +4      +7                                       Untreated controls average yield:                                                                  0.125   +1      +3                                       364 cwt/A U.S. No. 1, 394 cwt/A total                                                              0.0625  +9      +11                                      1-Nitro-3-(α,α,α,4-tetrafluoro- .sub.--m-                                        1.0     +13     +14                                      tolyl)guanidine      0.5     +5      +4                                                            0.25    +1      +1                                       Untreated controls average yield:                                                                  0.125   +2      +4                                       382 cwt/A U.S. No. 1, 412 cwt/A total                                                              0.0625  +5      +5                                       1-( .sub.--m-Methoxybenzyl)-3-nitroguanidine                                                       1.0     +10     +11                                                           0.5     +6      +6                                                            0.25    +4      +5                                       Untreated controls average yield:                                                                  0.125   +4      +5                                       362 cwt/A U.S. No. 1, 394 cwt/A total                                                              0.0625  +4      +5                                       1-(3,5-Dichlorophenyl)-3-nitro-                                                                    1.0     +11     +7                                       guanidine            0.5     +19     +18                                                           0.25    +10     +12                                      Untreated controls average yield:                                                                  0.125   +12     +10                                      364 cwt/A U.S. No. 1, 394 cwt/A total                                                              0.0625  +19     +18                                      1-Nitro-3-(α,α,α,4-tetrafluoro- .sub.--m-                                        1.0     +16     +12                                      tolyl)guanidine      0.5     +17     +17                                                           0.25    +11     +12                                      Untreated controls average yield:                                                                  0.125   +4      +4                                       382 cwt/A U.S. No. 1, 412 cwt/A total                                                              0.0625  +14     +13                                      1-( .sub.--m-Methoxybenzyl)-3-nitro-                                                               1.0     +5      +3                                       guanidine            0.5     +10     +9                                                            0.25    +8      +8                                       Untreated controls average yield:                                                                  0.125   +9      +8                                       331 cwt/A U.S. No. 1,366 cwt/A total                                                               0.0625  +7      +7                                       ______________________________________                                         (±) = Increase or decrease over untreated controls.                   

EXAMPLE 21 Evaluation of test compounds formulated as emulsifiableconcentrates or aqueous dispersions to determine their efficacy forincreasing the number of U.S. No. 1 potatoes and the total weight ofpotatoes produced per plant

In this evaluation, white potatoes, variety-Superior, are planted duringmid-April. Three weeks after the plants have emerged; plots, comprisingtwo 9.6 meter rows, spaced 0.9 meters apart, are sprayed with an aqueousdispersion of one of the follwoing formulations:

    ______________________________________                                                             Percent W/V                                              ______________________________________                                        (1) Compound                                                                  1-(3,5-Dichlorophenyl)-3-nitroguanidine                                                              11.0                                                   N--Methylpyrrolidone   38.0                                                   Tenneco 500/100 aromatic solvent                                                                     35.0                                                   Anionic-nonionic surfactant T-Mulz                                                                    6.0                                                   339 emulsifier                                                                Multifilm X-77 spreader-activator                                                                    10.0                                                                          100.0                                                  ______________________________________                                    

Tenneco 500/100 aromatic solvent is a product of Tenneco Oil Company,Houston, Tex.; having the following characteristics:

Specific gravity 15.56/15.56° C.: 0.860-0.875

Acidity: No free acid

Flash, TCC min. °F.: 100

Kouri-Butanol value--min.: 92

Aromatics, Vol. %--min.: 95

Distillation range temp.: Not below 290° F.

Multifilm X-77 is a product of Colloidal Products Corporation,Sausalito, Calif.; having the following characteristics:

Specific gravity 20/20° C.: 0.98

Density lb./gal. at 20° C.: 8.20

Surface tension, Dynes/cm at 20° C.: 31

T-Mulz 339 is a product of the Thompson-Hayward Chemical Company, KansasCity, Kans., and is a blend of anionic-nonionic emulsifying agents.

    ______________________________________                                                             Percent W/V                                              ______________________________________                                        (2) Compound                                                                  1-Nitro-3-(α,α,α,4-tetrafluoro                                                     11.0                                                    .sub.-- m-tolyl)guanidine                                                    NaOH                    2.3                                                   H.sub.2 O              86.7                                                                          100.0                                                  (3) Compound                                                                  1-( .sub.-- m-Methoxybenzyl)-3-nitroguanidine                                                        11.0                                                   N--Methylpyrrolidone   57.0                                                   C.sub.8 -C.sub.10 alcohol                                                                            24.0                                                   Emulphor EL 620         8.0                                                                          100.0                                                  ______________________________________                                    

Emulphor EL 620 is a polyoxyethylated vegetable oil marketed by GAFCorporation, New York, N. Y.

The treated plants are cared for in accordance with normal culturalpractices utilized in the growing of potatoes until they reach maturity.When said plants reach maturity, about 20 weeks after planting, they areharvested. The total number of U.S. No. 1 potatoes per plot and totalweight of all potatoes per plot are determined.

Data obtained are reported in Table XVIII below.

                  TABLE XVIII                                                     ______________________________________                                        EVALUATION OF FORMULATED TEST COMPOUNDS                                       TO DETERMINE THEIR EFFECTIVENESS                                              FOR INCREASING PRODUCTION OF U.S. NO. 1                                       POTATOES AND TOTAL WEIGHT OF                                                  POTATOES PRODUCED PER PLANT                                                                       PERCENT INCREASE                                                              OR DECREASE                                                           POTA-   OVER UNTREATED                                                        TOES    CONTROLS                                                              PER     RATE KG/HA                                                FORMULATION   PLANT     0.5    0.25 0.125                                                                              0.0625                               ______________________________________                                        #1            U.S. No. 1                                                                              +4     +5   +6   +6                                   1-(3,5-Dichlorophenyl)-3-                                                                   Total     +4     +5   +6   +6                                   nitroguanidine                                                                #2            U.S. No. 1                                                                              +6     +2    0   +6                                   1-Nitro-3-(α,α,α,4-tetra-                                                 Total     +8     +3    0   +6                                   fluoro- --m-tolyl)guanidine                                                   #3            U.S. No. 1                                                                              +11    +16  +8   +9                                   1-( .sub.--m-Methoxybenzyl)-3-                                                              Total     +11    +17  +7   +10                                  nitroguanidine                                                                ______________________________________                                         Untreated controls  U.S. No. 1 = 360 cwt/A; Total = 390 cwt/A.           

EXAMPLE 22 Evaluation of formulated test compounds for increasing thetotal weight of potatoes produced per plant (Variety-Russett-Burbank)

Following the procedure of Example 21, except that the evaluations areconducted in the north-western United States using white potatoes,Variety-Russett-Burbank, the formulations #2 and 190 3 described inExample 21 are evaluated. Data obtained are reported in Table XIX below.

                  TABLE XIX                                                       ______________________________________                                        EVALUATION OF FORMULATED TEST COMPOUNDS                                       FOR INCREASING THE TOTAL WEIGHT OF POTATOES                                   PER PLANT (VARIETY - RUSSET-BURBANK)                                                              PERCENT INCREASE                                                              OR DECREASE                                                                   OVER UNTREATED                                                       WEEK OF  CONTROLS                                                             POST AP- RATE KG/HA                                                FORMULATION  PLICATION  0.5    0.25 0.125                                                                              0.0625                               ______________________________________                                        #2           1          -3       0  +14   +6                                  1-Nitro-3-(α,α,α,4-tetra-                                                2          +8     +10   +9  +11                                  fluro- .sub.--m-tolyl)guanidine                                               #3           1          -1      -2   +2  +11                                  1-( .sub.--m-Methoxybenzyl)-3-                                                             2          +6     +14   +4   +2                                  nitroguanidine                                                                ______________________________________                                         Untreated controls = U.S. No. 1 = 465 cwt/A, Total = 494 cwt/A.          

EXAMPLE 23 Evaluation of test compounds for increasing total potatoyield and increasing production of U.S. No. 1 potatoes

The following evaluations are conducted to evaluate a variety of testcompounds as plant growth regulants effective for increasing the totalweight of potatoes produced by potato plants and also for increasing theproduction of U.S. No. 1 potatoes produced by said plants.

In these tests, potato plants, Superior variety, are grown in tubs inthe greenhouse. The tubs, 2 ft.×1 ft.×1 ft., each contain two plants,and two tubs per treatment are used for evaluation. Two weekspost-emergence the plants are sprayed with an aqueousacetone (50/50)mixture containing 0.25% of a nonionic wetting agent (nonylphenolcontaining 9 mols of ethylene oxide, oleic acid, and isopropanol) andsufficient test compound to provide 1 kg/ha of test compound. The plantsare grown to maturity and harvested. Results obtained are reported inTable XX below.

                  TABLE XX                                                        ______________________________________                                        EVALUATION OF TEST COMPOUNDS FOR                                              INCREASING TOTAL POTATO YIELD AND INCREASING                                  PRODUCTION OF U.S. NO. 1 POTATOES                                                           Total Tuber                                                                            Total U.S. No. 1                                                     Fresh Weight                                                                           Tuber Fresh Weight                                     Treatment       Percent (±) Untreated Controls                             ______________________________________                                        1-( .sub.-- m-Cyanophenyl)-3-                                                                 +4         --                                                 nitroguanidine                                                                Methyl  .sub.-- m-(3-nitro-                                                                   +5         +14                                                guanidine)benzoate                                                            1-( .sub.-- m-Ethoxyphenyl)-                                                                  +1          +8                                                3-nitroguanidine                                                              1-(4-Fluoro- .sub.-- m-tolyl)-                                                                +3         --                                                 3-nitroguanidine                                                              1-[ .sub.-- m-(Difluoromethoxy)-                                                              +31        --                                                 phenyl]-3-nitroguanidine                                                      1-Nitro-3-[ .sub.-- m-(2,2,2-tri-                                                             +9         --                                                 fluoro-1,1-dihydroxyethyl)-                                                   phenyl]guanidine                                                              1-(2-Fluoro-5-methylbenzyl)-                                                                  +17        +30                                                3-nitroguanidine                                                              1-(2-Fluoro-5-methoxy-                                                                        +9         +26                                                benzyl)-3-nitroguanidine                                                      1-(2-Fluoro-3-methyl-                                                                         +13        +22                                                benzyl)-3-nitroguanidine                                                      1-Nitro-3-[ .sub.-- m-(trifluoro-                                                             +7         +13                                                methoxy)phenyl]guanidine                                                      Untreated control average total yield: 337 Cwt/A.                             ______________________________________                                    

EXAMPLE 24 Evaluation of test compounds for increasing sugar yield fromsugar beets

In the following tests, sugar beets (Beta Vulgaris, L.) are plantedduring the third week of March in field plots. The plants are cared forin accordance with normal practices employed in the raising of sugarbeet crops, except that evaluation plots are sprayed, either 120 days or60 days prior to harvest, with aqueous dispersions of test compoundformulated as emulsifiable concentrates. When the plants reach maturity,the beets are harvested, and the sugar yield and raw juice puritydetermined for all treatments.

The formulated compositions evaluated in these tests are as follows:

    ______________________________________                                                          Percent W/V                                                 ______________________________________                                        (1) Compound                                                                  1-Nitro-3-(α,α,α,4-tetrafluoro-                                                 11.0                                                       .sub.-- m-tolyl)guanidine                                                    N--Methylpyrrolidine                                                                              38.0                                                      Substituted benzenes (aromatic                                                                    35.0                                                      solvent)                                                                      Alkylarylpolyoxyethylene glycol,                                                                  10.0                                                      fatty acid and propanol                                                       Octylphenoxy polyethoxy ethanol                                                                    6.0                                                      (nonionic-surfactant)                                                                             100.0                                                     (2) Compound                                                                  1-( .sub.-- m-Methoxybenzyl)-3-nitro-                                                             11.0                                                      guanidine                                                                     N--Methylpyrrolidone                                                                              38.0                                                      Alkylarylpolyoxyethylene glycol                                                                   10.0                                                      fatty acid and propanol                                                       Substituted benzenes (aromatic                                                                    35.0                                                      solvent)                                                                      Octylphenoxy polyethoxy ethanol                                                                    6.0                                                      (nonionic-surfactant)                                                                             100.0                                                     ______________________________________                                    

Data obtained are reported in Tables XXI and XXII below. In theseevaluations, test compounds were found to be effective on sugar beetsfor increasing recoverable sugar yields. For example, the compound1-(m-methoxybenzyl)-3-nitroguanidine applied at 1.0-0.25 lb/A 60 daysbefore harvest gave 611 lbs/A more recoverable sugar than the untreatedcontrols which yielded 6,130 lbs/A of sugar.

                                      TABLE XXI                                   __________________________________________________________________________    EVALUATION OF TEST COMPOUNDS APPLIED                                          120 DAYS BEFORE HARVEST FOR INCREASING                                        SUGAR YIELD FROM SUGAR BEETS (BETA VULGARIS, L.)                                                  PERCENT INCREASE                                                              OVER UNTREATED CONTROLS                                                  RATE PERCENT                                                                             RAW JUICE  RECOVERABLE                              FORMULATION    KG/HA                                                                              SUGAR PERCENT PURITY                                                                           SUGAR                                    __________________________________________________________________________    (1)            1.0  +5     0         +1                                       1-Nitro-3-(α,α,α,4-tetrafluoro-                                            0.25 +4    +1         +6                                        .sub.--m-tolyl)guanidine                                                                    0.0625                                                                             +5    +1         +4                                       (2)            1.0  +3     0         +7                                       1-( .sub.--m-Methoxybenzyl)-3-                                                               0.25 +3    +1         +4                                       0.0625         +4    0    +5                                                  Untreated controls                                                                           --   14.49 90.25      18.37                                                                         (6,130 lbs/A)                            __________________________________________________________________________

                                      TABLE XXII                                  __________________________________________________________________________    EVALUATION OF TEST COMPOUNDS APPLIED                                          60 DAYS BEFORE HARVEST FOR INCREASING                                         SUGAR YIELD FROM SUGAR BEETS ( BETA VULGARIS, L.)                                                 PERCENT INCREASE                                                              OVER UNTREATED CONTROLS                                                  RATE PERCENT                                                                             RAW JUICE  RECOVERABLE                              FORMULATION    KG/HA                                                                              SUGAR PERCENT PURITY                                                                           SUGAR                                    __________________________________________________________________________    (1)            1.0  +2    +1         +8                                       1-Nitro-3-(α,α,α,4-tetrafluoro-                                            0.25 +2    +1         +2                                        .sub.--m-tolyl)guanidine                                                                    0.625                                                                              +2    +1         +4                                       (2)            1.0  +3    +1         +10                                      1-( .sub.--m-Methoxybenzyl)-3-                                                               0.25 +1     0         +10                                      nitroguanidine 0.625                                                                              +1     0         +3                                       Untreated controls                                                                           --   14.62 90.17      18.22                                                                         (6,183 lbs/A)                            __________________________________________________________________________

EXAMPLE 25 Evaluation of test compounds as yield-enhancing agents forgarlic (Allium sativum cv Balady)

In this evaluation, garlic bulbs are planted in the field at a seedingrate of 475 kg/ha. Test plots include two ridges, 0.6 meters wide and 10meters in length. Thirty-one days after planting, the seedling plantsare sprayed with an aqueous suspension of test compound which providesfrom 0.063 to 0.5 kg/ha of compound being evaluated. The aqueoussuspension is prepared by dispersing an emulsifiable concentratecontaining the test compound in water. The emulsifiable concentrate hasthe following composition:

    ______________________________________                                        Compound            Percent W/W                                               ______________________________________                                        Nitroguanidine test compound                                                                      11.0                                                      N--Methylpyrrolidone                                                                              38.0                                                      Tenneco 500/100 aromatic solvent                                                                  35.0                                                      Anionic-nonionic surfactant                                                                        6.0                                                      T-Mulz 339 emulsifier                                                         Multifilm X-77 spreader-activator                                                                 10.0                                                                          100.0                                                     ______________________________________                                    

Six months after planting, the garlic is harvested, and the resultsobtained are reported in Table XXIII below.

                  TABLE XXIII                                                     ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR GARLIC                                                                    Fresh Weight of Bulbs                                  Compound       kg/ha   % (±) Untreated Control                             ______________________________________                                        1-(3,5-Dichlorophenyl)-                                                                      0.5     +8                                                     3-nitroguanidine                                                                             0.125   +5                                                     1-Nitro-3-(α,α,α,4-                                                        0.125   +13                                                    tetrafluoro- .sub.-- m-tolyl)-                                                               0.063   +4                                                     guanidine                                                                     1-( .sub.-- m-Methoxybenzyl)-                                                                0.5     +9                                                     3-nitroguanidine                                                                             0.125   +8                                                     Untreated control average yield: 17.3 m Ton/ha                                ______________________________________                                    

EXAMPLE 26 Evaluation of test compounds as yield-enhancing agents forcarrots (Daucus carota cv chantenay)

In this evaluation, carrots are planted in fields at a seeding rate of 9kg/hectare. Forty-six days after planting, the seedling plants aresprayed with aqueousacetone (50/50) dispersion containing test compoundand 0.25% of Multifilm X-77 spreader-activator. Plots used forevaluation include two ridges 0.6 meters wide and 10 meters in length.About four months after planting, the carrots are harvested, and theresults obtained reported in Table XXIV below.

                  TABLE XXIV                                                      ______________________________________                                        EVALUATION OF NITROGUANIDINE TEST COMPOUNDS                                   AS YIELD-ENHANCING AGENTS FOR CARROTS                                                        Rate    Fresh Weight of Roots                                  Compound       kg/ha   % (±) Untreated Control                             ______________________________________                                        1-(3,5-Dichlorophenyl)-                                                                      0.5      +1                                                    3-nitroguanidine                                                                             0.125    +6                                                    1-Nitro-3-(α,α,α,4-                                                        0.125   +17                                                    tetrafluoro- .sub.-- m-tolyl)-                                                               0.063   +26                                                    guanidine                                                                     1-( .sub.-- m-Methoxybenzyl)-                                                                0.5     +20                                                    3-nitroguanidine                                                                             0.125   +19                                                    Untreated control average yield 26.0 m ton/ha                                 ______________________________________                                    

EXAMPLE 27 Evaluation of test compounds as yield-enhancing agents forturnips (Brassica rapa cv white purple top globe)

In this evaluation, test compound is dissolved in an acetone/water(50/50) mixture containing test compound and 0.25% of Multifilm X-77spreader-activator. The test composition is applied post-emergently tothe foliage of turnips eight or twelve weeks after planting. Plots usedfor evaluation are single rows, 10 feet long, arranged on 100 centimetercenters. Six replicates per treatment are used, and the turnips areharvested about four months after planting. Data obtained are reportedin Table XXV below.

                  TABLE XXV                                                       ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR TURNIPS                                                          Rate     Fresh Weight of Roots                                  Treatment     kg/ha    % (±) Untreated Controls                            ______________________________________                                        1-( .sub.-- m-Methoxybenzyl)-                                                               2.0      +5                                                     3-nitroguanidine                                                                            0.5      +3                                                     Applied eight weeks                                                           post planting (Root                                                           thickness 1.25-2.5 cm)                                                        1-( .sub.-- m-Methoxybenzyl)-                                                               2.0      +29                                                    3-nitroguanidine                                                                            0.5      +5                                                     Applied twelve weeks                                                          post planting (Root                                                           thickness 3.8-7.5 cm)                                                         Untreated control average yield: 332 cwt/acre.                                ______________________________________                                    

EXAMPLE 28 Evaluation of test compounds as yield-enhancing agents forred table beets (Beta vulgaris cv green top bunching)

Following the procedure of Example 27 above, but substituting red tablebeets for turnips, demonstrates the yield-enhancing effects of thecompounds of the invention on red table beets. Data obtained arereported in Table XXVI below.

                  TABLE XXVI                                                      ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR RED TABLE BEETS                                                  Rate     Fresh Weight of Roots                                  Treatment     kg/ha    % (±) Untreated Controls                            ______________________________________                                        1-( .sub.-- m-Methoxybenzyl)-                                                               2.0      +13                                                    3-nitroguanidine                                                                            0.5       +5                                                    Applied eight weeks                                                           post planting (Plant                                                          height 7.5-15 cm)                                                             1-( .sub.-- m-Methoxybenzyl)-                                                               2.0      +14                                                    3-nitroguanidine                                                                            0.5       -2                                                    Applied 12 weeks post                                                         planting (Plant height                                                        20-40 cm)                                                                     ______________________________________                                    

EXAMPLE 29 Evaluation of test compounds as yield-enhancing agents fortulips [(Tulipa sylvestris cv Iverson (albino)]

In this evaluation, field-grown tulips are treated when about 100% ofthe tulips are in bud or when all are in late bloom. The plants aresprayed with an aqueous/acetone mixture (20/80) containing test compoundand 0.25% Multifilm X-77 spreader-activator. Plot sizes utilized in thisevaluation are 1 row×5 ft. long with each treatment replicated sixtimes. Bulbs are harvested six weeks after the late bloom treatment.Data obtained are reported in Table XXVII below.

                  TABLE XXVII                                                     ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR TULIPS                                                               Large Bulbs                                                                              Percent of                                                  Rate   Fresh Weight                                                                             Large Bulbs                                      Treatment    kg/ha    % (±) Untreated Controls                             ______________________________________                                        1-( .sub.-- m-Methoxybenzyl)-                                                              2.0      +26        +35                                          3-nitroguanidine                                                                           0.5      +80        +81                                          (100% in bud)                                                                 1-( .sub.-- m-Methoxybenzyl)-                                                              2.0        0         +5                                          3-nitroguanidine                                                                           0.5      +53        +49                                          (Full bloom)                                                                  ______________________________________                                    

EXAMPLE 30 Evaluation of test compounds as yield-enhancing agents forsunflowers (Helianthus annus cv Dohlgren DO164)

In this evaluation, sunflowers growing in 18 cm pots, spaced in rows 75cm apart, are treated at the V8, V11-12, V16, V20 (R1) or V22 (R2-5)stage of growth with aqueous dispersion of test compound. Test compoundsare dispersed in acetone/water mixtures (2:1 ratio) containing 0.25% ofa nonionic wetting agent (i.e., nonylphenol containing 9 moles ofethylene oxide, oleic acid, and isopropanol). The dispersions areapplied as aqueous sprays in sufficient amounts to provide 0.31 kg/hathereof to the test pots. Five months after planting, the seed heads areharvested, and the weight of seeds from each plant is determined. Dataobtained are reported in Table XXVIII below.

                  TABLE XXVIII                                                    ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR SUNFLOWERS                                                        Rate    Fresh Weight of Seeds                                  Treatment      kg/ha   % (±) Untreated Controls                            ______________________________________                                        1-(3,5-Dichlorophenyl)-                                                       3-nitroguanidine                                                              Applied at the following                                                      vegetative stages:                                                            V8             0.31    +17                                                    V11-12         0.31    +37                                                    V16            0.31    +26                                                    V20 (R1)       0.31    +29                                                    V22 (R2-5)     0.31     +5                                                    ______________________________________                                    

EXAMPLE 31 Evaluation of test compounds as yield-enhancing agents fortobacco (Nicotiana tabacum cv Coker 319)

In this evaluation, Coker 319 variety tobacco plants are grown in 22.5cm plastic pots, one plant per pot. The pots are placed in rows 50 cmapart, and four to six replicates per treatment are used for evaluation.

When the plants are 5, 45 or 115 centimeters in height, they are sprayedwith an aqueous dispersion of test compound previously formulated as aliquid flowable formulation. The liquid flowable formulation contains,on a percent w/w basis, 30% 1-(3,5-dichlorophenyl)-3-nitroguanidine,0.4% colloidal magnesium aluminum silicate, 1.5% naphthaleneformaldehyde condensate, 8% polyethylene glycol, 0.1% nonylphenolethylene oxide condensate (9-11 moles ethylene oxide), 0.1% sodiumlignosulfonate, 0.07% citric acid, 0.06% xanthan gum, 59.67% water and0.10% paraformaldehyde. The liquid flowable formulation is diluted withwater and 0.25% of the Multifilm X-77 spreader-activator(alkylarylpolyoxyethylene glycols, free fatty acids and isopropanol) inthe spray tank. The dispersion is sprayed on the plants in sufficientamounts to provide 0.25 kg/ha of test compound. The plants are grown tomaturity and then harvested. Data obtained are reported in Table XXIXbelow. It is also noted that treatment of the tobacco plants retardssenescence of the lower tobacco leaves and permits harvesting of allleaves in a single cutting.

                  TABLE XXIX                                                      ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR TOBACCO                                                           Rate    Dry Weight of Leaves                                   Treatment      kg/ha   % (±) Untreated Controls                            ______________________________________                                        1-(3,5-Dichlorophenyl)-                                                       3-nitroguanidine                                                              Applied at the follow-                                                        ing plant heights:                                                             5 cm          0.25    +38                                                     45 cm         0.25    +64                                                    115 cm         0.25    +112                                                   ______________________________________                                    

EXAMPLE 32 Evaluation of test compounds as yield-enhancing agents foronions (Allium cepa cv Italian Red)

In this evaluation, onions (Italian Red variety) are field planted, oneplant per 10 centimeters. Treatment plots used for evaluation includetwo ridges 0.6 meters wide and 10 meters in length. Thirty-seven daysafter planting, test plots are sprayed with an aqueous dispersion of oneof the following formulations:

    ______________________________________                                                             Percent W/W                                              ______________________________________                                        (1)                                                                           1-(3,5-Dichlorophenyl)-3-nitroguanidine                                                              11                                                     Tenneco 500/100 aromatic solvent                                                                     35                                                     Anionic-nonionic surfactant                                                                           6                                                     T-Mulz 339 emulsifier                                                         Multifilm X-77 spreader-activator                                                                    10                                                     N--Methylpyrrolidone   38                                                                            100                                                    (2)                                                                           1-( .sub.-- m-Methoxybenzyl)-3-nitroguanidine                                                        11                                                     Tenneco 500/100 aromatic solvent                                                                     35                                                     Anionic-nonionic surfactant                                                                           6                                                     T-Mulz 339 emulsifer                                                          Multifilm X-77 spreader-activator                                                                    10                                                     N--Methylpyrrolidone   38                                                                            100                                                    (3)                                                                           1-Nitro-3-(α,α,α,4-tetrafluoro- .sub.-- m-                                         11                                                     tolyl)guanidine                                                               Tenneco 500/100 aromatic solvent                                                                     35                                                     Anionic-nonionic surfactant                                                                           6                                                     T-Mulz 339 emulsifier                                                         Multifil X-77 spreader-activator                                                                     10                                                     Tetrahydrofuran        38                                                                            100                                                    ______________________________________                                    

Four months after treatment, the onions are harvested and the resultsobtained are reported in Table XXX below.

                  TABLE XXX                                                       ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR ONIONS                                                           Rate     Fresh Weight Per Bulb                                  Compound      kg/ha    % (±) Untreated Controls                            ______________________________________                                        1-(3,5-Dichloro-                                                                            0.5      +32                                                    phenyl)-3-nitro-                                                                            0.125    +22                                                    guanidine                                                                     1-Nitro-3-(α,α,α,4-                                                       0.125    +25                                                    tetrafluoro- .sub.-- m-tolyl)-                                                              0.063    +32                                                    guanidine                                                                     1-( .sub.-- m-Methoxybenzyl)-                                                               0.5      +21                                                    3-nitroguanidine                                                                            0.125    +23                                                    Untreated control average yield: 177 grams/bulb.                              ______________________________________                                    

EXAMPLE 33 Evaluation of test compounds as yield-enhancing agents forrutabaga (Brassica napus, variety napobrassica)

The test procedure employed for evaluation of test compounds asyield-enhancing agents for rutabagas is as follows: The rutabagas areplanted in early May; two months thereafter they are sprayed with anaqueous suspension of test compounds formulated as liquid flowableformulations described in Example 31. The rutabagas are harvested aboutfour months after planting, and the data are reported in Table XXXIbelow.

                  TABLE XXXI                                                      ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR RUTABAGAS                                                        Rate     Fresh Weight Per Tuber                                 Compound      kg/ha    % (±) Untreated Controls                            ______________________________________                                        1-Nitro-3-(α,α,α-                                                         0.125    +54                                                    trifluoro- .sub.-- m-tolyl)-                                                                0.5       +3                                                    guanidine                                                                     1-(3,5-Dichloro-                                                                            0.125    +39                                                    phenyl)-3-nitro-                                                                            0.5       +3                                                    guanidine                                                                     1-( .sub.-- m-Methoxybenzyl)-                                                               0.125    +19                                                    3-nitroguanidine                                                                            0.5       +8                                                    Untreated control average yield: 510 g/tuber                                  ______________________________________                                    

EXAMPLE 34 Evaluation of test compounds as yield-enhancing agents foralfalfa (Medicago sativa, cv Saranoc)

In this evaluation, aqueous dispersions of test compounds are sprayedpre-emergently on 12.5×12.5 cm fiber pots planted with alfalfa seeds.Each pot contains four plants, and each treatment is replicated fivetimes. The evaluation test compounds are dispersed in acetone/water(50/50) mixtures with 0.25% w/w of a nonionic wetting agent (nonylpheolcontaining 9 mols of ethylene oxide, oleic acid, and isopropanol) added.Six weeks after spraying at the first bloom stage of growth, the alfalfais clipped, and the number of alfalfa stems per pot is determined. Dataobtained are reported in Table XXXII below.

                  TABLE XXXII                                                     ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR ALFALFA                                                            Rate    Number of Stems                                       Compound        kg/ha   Per Pot                                               ______________________________________                                        1-(3,5-Dichloro-                                                                              0.06    11.8                                                  phenyl)-3-nitro-                                                                              0.03    12.4                                                  guanidine       0.015   14.4                                                                  0.0075  14.8                                                  Untreated control                                                                             --      11.2                                                  ______________________________________                                    

EXAMPLE 35 Evaluation of test compounds as yield-enhancing agents fortomatoes (Lycopersicon esculentum)

To evaluate test compounds as yield-enhancing agents for tomatoes,process tomatoes are planted in two-row beds with 45 centimeters betweenrows. Each plot consists of two rows, six meters in length, and plotsare sprayed with aqueous dispersions of test compound when the plantsreach first bloom. Compounds being evaluated are formulated as describedin Example 32. Aqueous dispersions are applied in sufficient amount toprovide about 1.0 kg/ha of test compound to the treated plots, and dataare taken when the tomatoes begin to ripen. Data obtained are reportedin Table XXXIII below.

                  TABLE XXXIII                                                    ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD-ENHANCING AGENTS FOR TOMATOES                                                          Rate    Kg. Tomatoes/Six Meter                                 Compound       kg/ha   Row for Two-Row Beds                                   ______________________________________                                        Untreated control                                                                            --      106.8                                                  1-( .sub.-- m-Methoxybenzyl)-                                                                1.0     113.8                                                  3-nitroguanidine                                                              ______________________________________                                    

EXAMPLE 36 Evaluation of test compounds for extending the shelf life ofcut flowers, i.e., daffodils (Narcissus pseudonarcissus)

Daffoldils are picked with fully-opened flower buds on the morning ofthe experiment. Stems are re-cut to 30 cm lengths and, within one-halfhour of harvest, flower stems are immersed to a depth of 10 cm in 2,000ml of the treating solution. The treating solution contains the testcompound at 100 ppm. It is prepared by dissolving 100 mg of1-nitro-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine in 100 ml acetone andbringing the volume to 2,000 ml with dionized water. Control solutionsconsist of 5% acetone in water and water alone.

After immersion in the test solution for three minutes, 30 minutes, 90minutes, 270 minutes, or 24 hours, three specimens, selected at random,are transferred to 450 ml deionized water in 0.5-liter, wide-mouth amberjars and held there until the experiment is terminated; three specimensremain in the treating solution for the duration of the test. Stems ofcontrol flowers are held in 5% acetone for 30 minutes and 24 hours(three specimens for each immersion time) bfore transferring todeionized water while three specimens remain in water for the durationof the experiment. Treatments are distributed randomly in the laboratorymaintained at about 21° C.-25° C. Normal daylight is supplemented withfluorescent lighting to provide 12-hour periods of light and dark.

Flowers are rated for decorative value two days and four dayspost-treatment. Each specimen is separately rated for appearance ofperianth and corona according to the scale shown below whereinincreasing numerical value indicates increasing senescence. Anunweighted mean value representing the overall appearance of the floweris then assigned to the treatment.

    ______________________________________                                        Decorative                                                                              Numerical                                                           Acceptability                                                                           Rating     Description                                              ______________________________________                                        A. Perianth                                                                   Acceptable                                                                              1          Fresh appearance, perianth                                                    smooth and flat, no visual                                                    evidence of senescence                                   Acceptable                                                                              2          Slight curling at margin                                 Acceptable                                                                              3          Slight wilting                                           Acceptable                                                                              4          Marginal discoloration                                                        (browning) and increased                                                      wilt                                                     Unacceptable                                                                            5          Pigment loss (translucence)                                                   in less than half perianth                               Unacceptable                                                                            6          Pigment loss (translucence)                                                   in more than half perianth                               Unacceptable                                                                            7          Completely desiccated and/or                                                  brown.                                                   B. Corona                                                                     Acceptable                                                                              1          Erect and firm                                           Acceptable                                                                              2          Expanding and flattening                                 Acceptable                                                                              3          Slight wilt, margin discolored                                                (brown)                                                  Unacceptable                                                                            4          Less than half wilted and/or                                                  brown, desiccated                                        Unacceptable                                                                            5          More than half wilted and/or                                                  brown, desiccated.                                       ______________________________________                                    

                  TABLE XXXIV                                                     ______________________________________                                        EXTENDED VASE LIFE OF DAFFODILS TREATED                                       FOR VARIOUS LENGTHS OF TIME IN 100 PPM of                                     1-NITRO-3-(α,α,α,4-TETRAFLUORO- .sub.-- m-TOLYL)GUANIDIN                         Flower Freshness At Indicated                                        Immersion                                                                              Time Post Treatment                                      Treatment     Time       Two Days  Four Days                                  ______________________________________                                        1-Nitro-3-(α,α,α4-tetra-                                                   3 minutes 1.8       2.5                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  30 minutes 1.7       2.5                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  90 minutes 1.7       2.7                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  270 minutes                                                                              1.3       2.2                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  24 hours   1.3       2.2                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  Duration   1.5       2.7                                        fluoro- .sub.-- m-tolyl)-guanidine                                            Acetone Control                                                                             30 minutes 2.2       3.5                                        Acetone Control                                                                             24 hours   2.3       3.8                                        Water Control Duration   2.2       3.3                                        ______________________________________                                    

The test is continued after the flowers have lost fresh-flowerdecorative value in order to continue observations on the stems. (J. L.Stoddart in British Plant Growth Regulator Group, Monograph No. 8, page1, in part defines senescence in plants as follows: "More precisely, inleaves, it relates to the loss of structural integrity andphotosynthetic competence in the chloroplast.") Retention of chlorophyllin daffodil flower stem (or scape) treated with the subject compoundafter untreated stems are depleted of chlorophyll, i.e., have turnedyellow or brown, is indicative of delayed senescence.

In this test, the flower stem is rated for color and general appearanceat 17 days and 25 days post treatment. Flower stems (scapes) are ratedindividually for color and turgidity and assigned numerical ratings asshown in the following Table XXXV. Increasing numerical value denotesprogressive loss of photosynthetic competence, depletion of chlorophyll,and loss of structural integrity; in sum, increasing senescenceterminating in death.

    ______________________________________                                        RATING SYSTEM                                                                 SENESCENCE RATING OF DAFFODIL                                                 CUT FLOWER STEMS (SCAPES)                                                     Numerical                                                                     Rating     Predominant Color and Appearance                                   ______________________________________                                        1          Green, turgid, i.e., little or no visual                                      evidence of senescence                                             2          Gray-green, turgid, i.e., slight senescence                        3          Yellow-green, turgid                                               4          Yellow, turgid                                                     5          Yellow-brown, turgid, i.e., advanced                                          senescence                                                         6          Brown, erect, i.e., complete senescence                            7          Brown, collapsed, death                                            ______________________________________                                    

                  TABLE XXXV                                                      ______________________________________                                        DELAYED SENESCENCE OF DAFFODIL CUT                                            FLOWER STEMS (SCAPES) TREATED WITH 100 PPM of                                 1-NITRO-3-(α,α,α,4-TETRAFLUORO- .sub.-- m-TOLYL)GUANIDIN                         Stem Color and Appearance At                                                  Indicated Time Post                                                  Immersion                                                                              Treatment                                                Treatment     Time       17 Days   25 Days                                    ______________________________________                                        1-Nitro-3-(α,α,α4-tetra-                                                   3 minutes 1.3       1.3                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  30 minutes 1.0       2.0                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  90 minutes 1.3       4.0                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  270 minutes                                                                              Not Rated 1.0                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  24 hours   1.3       5.3                                        fluoro- .sub.-- m-tolyl)-guanidine                                            1-Nitro-3-(α,α,α4-tetra-                                                  Duration   4.0       7.0                                        fluoro- .sub.-- m-tolyl)-guanidine                                            5% Acetone Control                                                                          30 minutes 4.7       7.0                                        5% Acetone Control                                                                          24 hours   5.7       7.0                                        Water Control Duration   5.3       7.0                                        ______________________________________                                    

EXAMPLE 37 Evaluation of test compounds as yield-enhancing agents foralfalfa

The procedure of Example 34 is repeated except that1-(3,5-dichlorophenyl)-3-nitroguanidine is applied at rates of from 3.5g/ha to 20 g/ha with the results of the tests reported as alfalfa dryweight (±) percent of control. Data are reported in Table XXXVI below.

                  TABLE XXXVI                                                     ______________________________________                                        EVALUATION OF TEST COMPOUNDS                                                  AS YIELD ENHANCING AGENTS FOR ALFALFA                                                          Alfalfa dry weight                                           Compound         (±) % of control                                          ______________________________________                                        Untreated control                                                                              --                                                           1-(3,5-Dichlorophenyl)-                                                       3-nitroguanidine                                                              20 g/ha           +8.0                                                        15 g/ha          +20.0                                                        7.5 g/ha         +39.0                                                        3.5 g/ha         +25.0                                                        ______________________________________                                    

EXAMPLE 38 Evaluation of test compounds as yield enhancing agents forapples

In this evaluation test compounds are dispersed in 50/50 acetone/watermixtures in sufficient quantity to provide dispersions or solutionscontaining 0, 10, 100 or 1000 ppm of active ingredient and about 0.25%by volume of a nonionic wetting agent (nonylphenol containing 9 mols ofethylene oxide, oleic acid and isopropanol). Test dispersions areapplied to apple (Malus sylvestris Mill. cv. Oregon Spur Delicious)trees in the spring at the time of peak bloom. All test solutions aresprayed to run off. Each treatment utilizes two trees selected at randomfrom a block of uniformly blossoming individuals. During the growingseason, the orchard in which the experiment is conducted is sprayed withnormal fungicides and insecticides. Treatments are consistent withrecommended cultural practices. At the end of the season, fruit fromeach tree is harvested, weighed and the average weight of fruit per treedetermined. The results are reported in Table XXXVII below.

                  TABLE XXXVII                                                    ______________________________________                                        EVALUATION OF TEST COMPOUNDS AS                                               YIELD ENHANCING AGENTS FOR APPLES                                                             Rate    Average yield tree                                    Compound        (ppm)   (lb. of fruit)                                        ______________________________________                                        1-(3,5-Dichloro-                                                                              1000    57.5                                                  phenyl)-3-nitro-                                                                               100    61.5                                                  guanidine        10     62.3                                                  Control           0     39.3                                                  1( .sub.-- m-Methoxybenzyl)-                                                                  1000    36.3                                                  3-nitroguanidine                                                                               100    62.8                                                                   10     58.5                                                  Control           0     47.5                                                  ______________________________________                                    

EXAMPLE 39 Extended shelf life of swiss chard

The deterioration of cut leaves of swiss chard is slowed following abrief dip of the leaves in a solution containing1-(m-methoxybenzyl)-3-nitroguanidine in acetone to produceconcentrations of test compound in the range of 8 to 512 ppm. Leaves arecut from field-grown swiss chard plants and each leaf is cut in halflengthwise, with one piece being dipped for 60 seconds in test solutionand the second for 60 seconds in a solution of H₂ O and the appropriatecontrol level of acetone (no separate acetone effect is observed). Theleaf pieces are drained and then laid in trays with moist toweling.After four days at 20° C., the trays are exposed to 30° C. for anotherfour days. Senescence is monitored by visual observation of the loss ofchlorophyll and/or progression of necrosis of the leaves. The effectiveconcentration range is above 8 or 64 ppm.

    ______________________________________                                        Treatment (ppm)   Retardation of                                              1-( .sub.-- m-methoxybenzyl)-3-                                                                 Senescence, %                                               nitroguanidine    of control                                                  ______________________________________                                        1                  0                                                          8                 25                                                          64                70                                                          512               75                                                          ______________________________________                                    

EXAMPLE 40 Extending vase life of cut gladiolus flowers by treating withsubstituted nitroguanidines

The vase life of cut flowers is the length of time that the flowerretains its decorative value. Vase life is, in part, determined by thecut stem's ability to continue to conduct nutrients and water to, andprovide support for the flower. The ability is especially important forflowers whose stems bear many florets, such as, for example, thegladiolus. When such flowers are cut with closed buds which eventuallyopen while in the vase and when bud-opening is acropretally with time,maximum vase life is especially dependent upon a functioning stem.

Gladiolus flowers are obtained from a local nursery distributor andtransported to the laboratory wrapped and boxed as customary in thetrade. Stems are recut to 30 cm lengths in a cold-room maintained at 4°C. and 60% rh and immersed in a solution, hereafter referred to as thetreating solution of the following composition:

    ______________________________________                                        Component              g/l                                                    ______________________________________                                        Sucrose                20.00                                                  Citric acid, monohydrate                                                                             4.20                                                   8-Hydroxyquinoline citrate                                                                           0.20                                                   Deionized water        ca. 900 ml                                             Reaction adjusted to pH 4.6 with 10 molar solution of                         potassium hydroxide (about 3.9 mL/l of medium).                               Deionized water        qs 1000 ml                                             ______________________________________                                    

Jars are distributed at random around the laboratory which is maintainedat 21° C. to 25° C. Normal daylight is supplemented with fluorescentlighting to provide 12 hour periods of light. Appropriate holdingsolution is replenished as needed.

Flowers are rated for decorative value five days post-treatment. Theoverall appearance of all open florets on each of the five stems perreplicate (two replicates per treatment) is assigned a single ratingbased on the scale shown below in which increasing numerical valueindicates increasing senescence. The rating provides a single valuewhich reflects the range of the severity of wilting or senescence shownby the individual florets on each stem.

    ______________________________________                                        Freshness rating of cut gladiolus                                             Flower: Severity of floret wilt and browning                                  Decorative Numerical                                                          Acceptability                                                                            Score       Description                                            ______________________________________                                        Acceptable 1           Fresh, no wilt                                                    1.5         Trace wilt (curl)                                                             @ margin                                                          2           Slight wilt extending                                                         beyond margin                                                     2.5         Moderate wilt with                                                            slight marginal browning                               Unacceptable                                                                             3           Pronounced wilt and                                                           browning                                                          3.5         Severe wilt, browning                                                         with areas of desiccation                                         4           Complete wilt and                                                             desiccation                                            ______________________________________                                    

An additional rating, based on the scale shown below, is assigned toreflect the extent of the wilting, i.e., the proportion of wiltedflorets.

    ______________________________________                                        Freshness rating of cut gladiolus                                             Flowers: Extent of wilting                                                    Decorative    Proportion of                                                   Acceptability wilted florets %                                                ______________________________________                                        Acceptable     0                                                                             0-10                                                                         10-25                                                                         25-50                                                           Unacceptable  50-75                                                                          75-100                                                                       100                                                             ______________________________________                                    

The numbers of open florets and healthy opening buds, i.e., budsexposing at least 1 cm length of petal with no visible discoloration,step color and turgor, and bud color, are also recorded. Color changesaccompanying senescence are shown in the rating system below.

    ______________________________________                                        Freshness rating of cut galdiolus stem by color                                                       Increasing                                            Rating       Color      Senescence                                            ______________________________________                                        Dk gn        Dark green ↓                                              Gn           Green      ↓                                              YG           Yellow-green                                                                             ↓                                              Y            Yellow     ↓                                              Br           Brown      ↓                                              ______________________________________                                    

The results of this experiment are shown below in Table XXXVIII.

                                      TABLE XXXVIII                               __________________________________________________________________________    Extended vase life of cut gladiolus flowers                                   treated with 100 ppm solutions of several substitution nitroquanidines                    Number of                                                                              Floret wilt                                                          Open                                                                              Opening                                                                            Extent   Stem                                                                              Color of                                    Treatment   Florets                                                                           Buds %   Severity                                                                           wilt                                                                              Stem Bud                                    __________________________________________________________________________    Untreated (DIW)                                                                           19   5   50-75                                                                             3.0  sh/med                                                                            Y6   Y6/Br                                  Control (DIW)                                                                             25   9   10-25                                                                             2.5  slt YG/Gn                                                                              YG/Gn                                  Control (Ac)                                                                              21  11   10-25                                                                             2.5  slt YG/Gn                                                                              Y6                                     1-Nitro-3-(α,α,α,-tri-                                                  23  42   0   1.0  nil Dk Gn                                                                              Gn                                     fluoro- .sub.--m-tolyl)guanidine                                              1-((3,5-dichlorophenyl)-                                                                  49  15   0   1.0  nil Dk Gn                                                                              Gn                                     3-nitroguanidine                                                              1-Nitro-3-(α, α, α,4-                                                   17  37   0   1.0  nil Dk Gn                                                                              Gn                                     tetrafluoro- .sub.--m-tolyl)-                                                 guanidine                                                                     1-( .sub.--m-methoxybenzyl)-3-                                                            42  21   0   1.0  mL  Dk Gn                                                                              Gn                                     nitroguanidine                                                                AOAA        18  35    0-10                                                                             1.5  nil Dk Gn                                                                              Gn                                     __________________________________________________________________________

It is seen that treating cut gladiolus flowers by immersing stems for 30minutes in solutions of substituted nitroguanidines substantiallyextends the vase life of such flowers as compared to the vase life offlowers not so treated. The extension so obtained is based on severalcriteria including, increased number of acceptable open florets,increased number of healthy opening buds, reduction in both severity andextent of floret wilt, superior retention of green color in stems andbuds, and superior retention of stem turgor.

EXAMPLE 41 Delayed senescence in leafy green vegetables

Kale and collard greens are brought at local farmers market andrefrigerated in plastic bags until needed. The outermost leaves arediscarded, and young, healthy, undamaged leaves are used for theexperiment. Leaves are removed from the stalk by cutting with a sharpscalpel at the point of attachment. Immediately after removal, thepetiole is inserted into the treating solutions contained in 4 ouncewide-mouth amber jars. In order to provide support for the leaf and tominimize loss of solution by evaporation, the jars are stoppered withplastic foam plugs which previously had a radial cut made with a scalpelto accommodate the leaf petiole.

A treating solution with the experimental compound at 100 ppm isprepared by dissolving 200 mg of1-nitro-3-(α,α,α,4-tetrafluoro-m-tolyl)guanidine in 100 ml acetone andbringing to a final volume of 2000 ml with deionized water. Treatingsolutions with the experimental compound at 10 ppm and 1 ppm are made by10 fold serial dilution using 5% aqueous acetone as the diluent. Controlsolutions consisting of 5% aqueous acetone and water alone are includedin the experiment.

All treatments, with both kale and collard greens, are replicated fourtimes, each replicate leaf deriving from a different plant. The jars arerandomly distributed throughout the laboratory maintained at 21° C. to25° C. Normal daylight is supplemented by fluorescent lighting toprovide 12 hour periods of light and dark. The treating solutions arereplenished as needed using a funnel with its stem inserted through theradial cut of the foam stopper. Leaves are rated for retention of greencolor at one, three and seven days after initiation of treatment. Colorchanges accompanying advancing senescence are shown in the rating systembelow.

    ______________________________________                                        Color                   Increasing                                            Code         Color      Senescence                                            ______________________________________                                        1            Dark Green ↓                                              2            Green      ↓                                              3            Light Green                                                                              ↓                                              4            Yellow Green                                                                             ↓                                              5            Yellow     ↓                                              6            Brown      ↓                                              ______________________________________                                    

The average ratings for the treatments on each of the observation daysare shown in Table XL.

                  TABLE XL                                                        ______________________________________                                        RETENTION OF CHLOROPHYL AND DELAY OF                                          SENESCENCE IN ISOLATED KALE AND COLLARD                                       LEAVES TREATED WITH SOLUTIONS 1-NITRO-3-                                      (α,α,α,4-TETRAFLUORO-M--TOLYL)GUANIDINE                     Concentration of                                                              1-nitro-3-(α,α,α,-                                                          Leaf color after 1, 3 and 7                                   4-tetrafluoro- .sub.-- m-                                                                     days after treatment                                          tolyl)guanidine Kale         Collard                                          PPM             1     3        7   1   3     7                                ______________________________________                                        100             1.0   1.0      1.8 1.0 1.1   2.8                              10              1.0   1.0      1.0 1.0 1.0   3.5                              1               1.0   1.0      2.0 1.0 1.3   3.7                              (5% acetone)    1.0   1.0      5.3 1.0 2.3   4.5                              (DIW)           1.0   2.0      5.3 1.0 3.3   3.8                              ______________________________________                                    

These results demonstrate the delay of onset and progress of senescencein treated leaves.

What is claimed is:
 1. A method for inducing a cytokinin-like responsein ornamental and crop plants, said method comprising: applying to thefoliage of said plants or to soil containing seeds or other propagatingorgans thereof, a cytokinin-like-response-inducing amount of a compoundrepresented by the structural formula, ##STR26## wherein W₅ is H, F orCl; X₅ is H, straight or branched C₁ -C₄ alkyl, halogen, CN, NO₂, CH₂CN.OCHF₂, OCF₂ CHF₂, OCF₃, CF₃, C₁ -C₄ alkoxy, OH, C(OH)₂ CF₃, COCH₃,N(CH₃)₂, or CH₂ OR₃ where R₃ is H or CH₃ ; Y₅ is H, OH, OCH₃, CH₃ orhalogen; Z₅ is H, CH₃, halogen, OCH₃ or CF₃ ; R₄ is H, CH₃ C₂ H₅ of CF₃; R₅ is H or CH₃ ; R₆ is NO₂ or CN; m is an integer of 0, 1 or 2; n isan integer of 0 or 1; and the salts or tautomers thereof.
 2. A methodaccording to claim 1, wherein said compound is1-(m-hydroxybenzyl)-3-nitroguanidine.
 3. A method according to claim 1,wherein said compound is 1-benzyl-3-cyanoguanidine.
 4. A methodaccording to claim 1, wherein said compound is1-cyano-3-(α,α,α-trifluoro-m-tolyl)guanidine.
 5. A method according toclaim 1, wherein said compound is 1-(m-bromophenyl)-3-nitroguanidine. 6.A method according to claim 1, wherein said compound is1-(m-methoxybenzyl)-3-nitroguanidine.
 7. A compound according to claim1, wherein said compound is1-(2-fluoro-3-methoxybenzyl)-3-nitroguanidine.
 8. A method according toclaim 1, wherein said compound is 1-(m-ethoxybenzyl)-3-nitroguanidine.9. A method according to claim 1, wherein said compound is1-(m-sec-butoxybenzyl)-3-nitroguanidine.
 10. A method according to claim1, wherein said compound is 1-nitro-3-(m-propoxybenzyl)guanidine.
 11. Amethod according to claim 1, wherein said compound is1-(o-fluorobenzyl)-3-nitroguanidine.
 12. A method according to claim 1,wherein said compound is 1-(m-iodobenzyl)-3-nitroguanidine.
 13. A methodaccording to claim 1, wherein said compound is1-(m-chlorobenzyl)-3-nitroguanidine.
 14. A method according to claim 1,wherein said compound is 1-(m-bromobenzyl)-3-nitroguanidine.
 15. Acompound according to claim 1, wherein said compound is1-(m-fluorobenzyl)-3-nitroguanidine.
 16. A compound according to claim1, wherein said compound is 1-(m-methylbenzyl)-3-nitroguanidine.
 17. Amethod according to claim 1, wherein said compound is1-nitro-3-[m-(trifluoromethyl)benzyl]guanidine.
 18. A method accordingto claim 1, wherein said compound is1-(2,5-difluorobenzyl)-3-nitroguanidine.
 19. A method according to claim1, wherein said compound is1-(2-fluoro-5-methoxybenzyl)-3-nitroguanidine.
 20. A method according toclaim 1, wherein said compound is1-(2-fluoro-5-methylbenzyl)-3-nitroguanidine.
 21. A method according toclaim 1, wherein said compound is1-(2,4-difluorobenzyl)-3-nitroguanidine.
 22. A method according to claim1, wherein said compound is 1-(2,4-dichlorobenzyl)-3-nitroguanidine. 23.A method according to claim 1, wherein said compound is1-(α-methylbenzyl)-3-nitroguanidine.
 24. A method according to claim 1,wherein said compound is 1-(m-α-dimethylbenzyl)-3-nitroguanidine.
 25. Amethod according to claim 1, wherein said compound is1-nitro-3-[α-(trifluoromethyl)benzyl]guanidine.
 26. A method accordingto claim 1, wherein said compound is 1-(α-ethylbenzyl)-3-nitroguanidine.